SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "L773:1434 6621 OR L773:1437 4331 "

Sökning: L773:1434 6621 OR L773:1437 4331

  • Resultat 1-50 av 201
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Aardal, Elisabeth, et al. (författare)
  • Cortisol in Saliva : Reference Ranges and Relation to Cortisol in Serum
  • 1995
  • Ingår i: European Journal of Clinical Chemistry and Clinical Biochemistry. - : Walter de Gruyter GmbH. - 0939-4974. ; 33, s. 927-932
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this study was to establish morning and evening reference ranges for cortisol in saliva. Another objective was to compare the concentrations of the mainly free cortisol in saliva to those of total cortisol in serum as determined with a commercial radioimmunoassay. The concentrations were determined in matched samples of saliva and serum collected at 8am and 10pm from 197 healthy volunteers. The saliva samples were stable for at least 7 days at room temperature and for 9 months at —20 °C. Reference ranges, the central 95%, were estimated to 3.5—27.0 nmol/1 at 8 am and < 6.0 nmol/1 at 10 pm. The intra-assay coefficient of variation (CV) was below 5% and total CV below 10%. The relation between the cortisol concentrations in serum and saliva was nonlinear with r = 0.86 for serum concentrations < 450 nmol/1 and r = 0.44 for serum concentrations ^ 450 nmol/1. In conclusion, the satisfactory precision of the analysis and the simple non-invasive sampling procedure suggest that saliva may be used for cortisol measurements in situations where blood sampling is difficult to perform.
  •  
2.
  • Aardal-Eriksson, Elisabeth, et al. (författare)
  • Salivary cortisol : an alternative to serum cortisol determinations in dynamic function tests
  • 1998
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - 1434-6621 .- 1437-4331. ; 36:4, s. 215-222
  • Tidskriftsartikel (refereegranskat)abstract
    • Salivary cortisol was measured as an alternative to serum cortisol as a marker for adrenocortical function following insulin tolerance test, corticotropin-releasing-hormone stimulation and adreno-corticotrophic hormone stimulation. During insulin tolerance test and corticotropin-releasing-hormone stimulation adreno-corticotrophic hormone was also measured. The tests were performed on healthy control subjects as well as on patients under investigation for various disturbances in the hypothalamic-pituitary-adrenocortical axis (insulin tolerance test: 3 controls on two occasions and 14 patients; corticotropin-releasing-hormone stimulation: 4 controls and 18 patients; adreno-corticotrophic hormone stimulation: 6 controls and 10 patients). Five patients underwent both insulin tolerance test and corticotropin-releasing-hormone stimulation. Using criteria for adequate cortisol response in serum, the patients were classified as good or poor responders. In 42 of the 45 tests performed the same conclusion as to cortisol status was drawn when based on serum and salivary cortisol responses. In healthy subjects and good responders the mean cortisol relative increase was greater in saliva than in serum in all three tests (p < 0.05). Characteristic of the results for the insulin tolerance test was a significant initial mean decrease (p < 0.05), not found in serum, and the highest observed salivary cortisol value was delayed for at least 30 minutes compared to that in serum. Plasma adreno-corticotrophic hormone correlated significantly with the cortisol concentrations determined 15 minutes later in serum (r = 0.54–0.64) and in saliva (r = 0.76–0.85). The more pronounced cortisol response in saliva than in serum and its closer correlation with adreno-corticotrophic hormone offer advantages over serum cortisol, suggesting salivary cortisol measurement may be used as an alternative parameter in dynamic endocrine tets.
  •  
3.
  • Andrade, Luis E. C., et al. (författare)
  • International consensus on antinuclear antibody patterns : definition of the AC-29 pattern associated with antibodies to DNA topoisomerase I
  • 2018
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : WALTER DE GRUYTER GMBH. - 1434-6621 .- 1437-4331. ; 56:10, s. 1783-1788
  • Tidskriftsartikel (refereegranskat)abstract
    • The indirect immunofluorescence assay (IFA) on HEp-2 cells is the reference method for autoantibody screening. The HEp-2 IFA pattern provides useful information on the possible autoantibodies in the sample. The International Consensus on Antinuclear Antibody Patterns (ICAP) initiative seeks to define and harmonize the nomenclature of HEp-2 IFA patterns. The most relevant and usual patterns have been assigned an alphanumeric code from anti-cell (AC)-1 to AC-28 and were organized into a classification algorithm (www.ANApatterns.org). The systemic sclerosis-associated autoantibodies to DNA topoisomerase I (Topo I) produce a peculiar composite 5-element HEp-2 IFA pattern (Topo I-like pattern) comprising the staining of the nucleus, metaphase chromatin plate, nucleolar organizing region, cytoplasm and nucleolus. In a recent assessment of the European Consensus Finding Study Group on autoantibodies, a well-defined anti-Topo I sample was blindly analyzed and classified according to ICAP AC patterns by 43 participant laboratories across Europe. There were wide variations among these laboratories in reporting nuclear, nucleolar and cytoplasmic patterns, indicating the inadequacy of the existing AC patterns to report the Topo I-like pattern. Several ICAP member laboratories independently demonstrated the overall consistency of the HEp-2 IFA Topo I-like pattern using HEp-2 slides from different manufacturers. The ICAP committee reviewed 24 candidate images and selected the four most representative images to be available on the ICAP website. The proper recognition of the AC-29 pattern should trigger suspicion of the presence of anti-Topo I antibodies, which may engender appropriate analyte-specific reflex tests to confirm the autoantibody specificity.
  •  
4.
  • Andreasson, Ulf, 1968, et al. (författare)
  • Assessing the commutability of candidate reference materials for the harmonization of neurofilament light measurements in blood
  • 2023
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 61:7, s. 1245-1254
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives Neurofilament light chain (NfL) concentration in blood is a biomarker of neuro-axonal injury in the nervous system and there now exist several assays with high enough sensitivity to measure NfL in serum and plasma. There is a need for harmonization with the goal of creating a certified reference material (CRM) for NfL and an early step in such an effort is to determine the best matrix for the CRM. This is done in a commutability study and here the results of the first one for NfL in blood is presented.Methods Forty paired individual serum and plasma samples were analyzed for NfL on four different analytical platforms. Neat and differently spiked serum and plasma were evaluated for their suitability as a CRM using the difference in bias approach.Results The correlation between the different platforms with regards to measured NfL concentrations were very high (Spearman's rho >= 0.96). Samples spiked with cerebrospinal fluid (CSF) showed higher commutability compared to samples spiked with recombinant human NfL protein and serum seems to be a better choice than plasma as the matrix for a CRM.Conclusions The results from this first commutability study on NfL in serum/plasma showed that it is feasible to create a CRM for NfL in blood and that spiking should be done using CSF rather than with recombinant human NfL protein.
  •  
5.
  • Andreasson, Ulf, 1968, et al. (författare)
  • Commutability of the certified reference materials for the standardization of beta-amyloid 1-42 assay in human cerebrospinal fluid: lessons for tau and beta-amyloid 1-40 measurements
  • 2018
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 56:12, s. 2058-2066
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The core Alzheimer's disease cerebrospinal fluid (CSF) biomarkers total tau (T-tau), phosphorylated tau (P-tau), beta-amyloid 1-42 (A beta 42) and beta-amyloid 1-40 (A beta 40) are increasing in importance and are now part of the research criteria for the diagnosis of the disease. The main aim of this study is to evaluate whether a set of certified reference materials (CRMs) are commutable for A beta 42 and to serve as a feasibility study for the other markers. This property is a prerequisite for the establishment of CRMs which will then be used by manufacturers to calibrate their assays against. Once the preanalytical factors have been standardized and proper selection criteria are available for subject cohorts this harmonization between methods will allow for universal cut-offs to be determined. Methods: Thirty-four individual CSF samples and three different CRMs where analyzed for T-tau, P-tau, A beta 42 and A beta 40, using up to seven different commercially available methods. For A beta 40 and A beta 42 a mass spectrometry-based procedure was also employed. Results: There were strong pairwise correlations between the different methods (Spearman's p>0.92) for all investigated analytes and the CRMs were not distinguishable from the individual samples. Conclusions: This study shows that the CRMs are commutable for the different assays for A beta 42. For the other analytes the results show that it would be feasible to also produce CRMs for these. However, additional studies are needed as the concentration interval for the CRMs were selected based on A beta 42 concentrations only and did in general not cover satisfactory large concentration intervals for the other analytes.
  •  
6.
  • Apweiler, Rolf, et al. (författare)
  • Approaching clinical proteomics : current state and future fields of application in fluid proteomics
  • 2009
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - 1434-6621 .- 1437-4331. ; 47:6, s. 724-744
  • Forskningsöversikt (refereegranskat)abstract
    • The field of clinical proteomics offers opportunities to identify new disease biomarkers in body fluids, cells and tissues. These biomarkers can be used in clinical applications for diagnosis, stratification of patients for specific treatment, or therapy monitoring. New protein array formats and improved spectrometry technologies have brought these analyses to a level with potential for use in clinical diagnostics. The nature of the human body fluid proteome with its large dynamic range of protein concentrations presents problems with quantitation. The extreme complexity of the proteome in body fluids presents enormous challenges and requires the establishment of standard operating procedures for handling of specimens, increasing sensitivity for detection and bioinformatical tools for distribution of proteomic data into the public domain. From studies of in vitro diagnostics, especially in clinical chemistry, it is evident that most errors occur in the preanalytical phase and during implementation of the diagnostic strategy. This is also true for clinical proteomics, and especially for fluid proteomics because of the multiple pretreatment processes. These processes include depletion of high-abundance proteins from plasma or enrichment processes for urine where biological variation or differences in proteolytic activities in the sample along with preanalytical variables such as inter- and intra-assay variability will likely influence the results of proteomics studies. However, before proteomic analysis can be introduced at a broader level into the clinical setting, standardization of the preanalytical phase including patient preparation, sample collection, sample preparation, sample storage, measurement and data analysis needs to be improved. In this review, we discuss the recent technological advances and applications that fulfil the criteria for clinical proteomics, with the focus on fluid proteomics. These advances relate to preanalytical factors, analytical standardization and quality-control measures required for effective implementation into routine laboratory testing in order to generate clinically useful information. With new disease biomarker candidates, it will be crucial to design and perform clinical studies that can identify novel diagnostic strategies based on these techniques, and to validate their impact on clinical decision-making.
  •  
7.
  • Arfvidsson, Berndt, et al. (författare)
  • S100B concentrations increase perioperatively in jugular vein blood despite limited metabolic and inflammatory response to clinically uneventful carotid endarterectomy
  • 2015
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 53:1, s. 111-117
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Our aim was to test the hypothesis that metabolic and inflammatory responses of the brain perioperatively during carotid endarterectomy (CEA) might affect blood brain barrier (BBB) integrity.Methods: Twenty patients with >70% stenosis of internal carotid artery (ICA) were prospectively included. Surgery was performed under general anaesthesia. Blood was sampled from ipsilateral internal jugular vein and radial artery: just before, during, and after ICA clamping S100B protein, glucose, lactate, 20 amino acids, and key cytokines were analysed.Results: Jugular vein S100B increased during clamping and reperfusion, while a marginal systemic increase was recorded, unrelated to stump pressure during clamping. Glucose increased during clamping in jugular vein blood and even more systemically, while jugular lactate values were higher than systemic values initially. Most amino acids did not differ significantly between jugular vein and systemic levels: glutamic acid and aspartic acid decreased during surgery while asparagine increased. Jugular vein interleukin (IL)-6 showed a transient non-significant increase during clamping and decreased systemically. IL-8 and IL-10 increased over time.Conclusions: Rising jugular vein S100B concentrations indicated reduced BBB integrity, and marginal secondary increase of S100B systemically. Limited ischaemic effects on the brain during cross-clamping, unrelated to S100B concentrations, were confirmed by lower brain glucose levels and higher lactate levels than in systemic blood. The lack of increased jugular vein glutamic acid disproves any major ischaemic brain injury following CEA. The inflammatory response was limited, did not differ greatly between jugular and systemic blood, and was unrelated to S100B.
  •  
8.
  • Arslan, Burak, 1990, et al. (författare)
  • Blood-based biomarkers in Alzheimer's disease - moving towards a new era of diagnostics
  • 2024
  • Ingår i: CLINICAL CHEMISTRY AND LABORATORY MEDICINE. - 1434-6621 .- 1437-4331.
  • Tidskriftsartikel (refereegranskat)abstract
    • Alzheimer's disease (AD), a primary cause of dementia globally, is traditionally diagnosed via cerebrospinal fluid (CSF) measures and positron emission tomography (PET). The invasiveness, cost, and limited accessibility of these methods have led to exploring blood-based biomarkers as a promising alternative for AD diagnosis and monitoring. Recent advancements in sensitive immunoassays have identified potential blood-based biomarkers, such as A beta 42/A beta 40 ratios and phosphorylated tau (p-tau) species. This paper briefly evaluates the clinical utility and reliability of these biomarkers across various AD stages, highlighting challenges like refining plasma A beta 42/A beta 40 assays and enhancing the precision of p-tau, particularly p-tau181, p-tau217, and p-tau231. The discussion also covers other plasma biomarkers like neurofilament light (NfL), glial fibrillary acidic protein (GFAP), and synaptic biomarkers, assessing their significance in AD diagnostics. The need for ongoing research and development of robust assays to match the performance of CSF and PET biomarkers is underscored. In summary, blood-based biomarkers are increasingly crucial in AD diagnosis, follow-up, prognostication, treatment response evaluation, and population screening, particularly in primary care settings. These developments are set to revolutionize AD diagnostics, offering earlier and more accessible detection and management options
  •  
9.
  • Arslan, Burak, 1990, et al. (författare)
  • Neurofilament light chain as neuronal injury marker - what is needed to facilitate implementation in clinical laboratory practice?
  • 2023
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 61:7, s. 1140-1149
  • Tidskriftsartikel (refereegranskat)abstract
    • Neurobiomarkers have attracted significant attention over the last ten years. One promising biomarker is the neurofilament light chain protein (NfL). Since the introduction of ultrasensitive assays, NfL has been developed into a widely used axonal damage marker of relevance to the diagnosis, prognostication, follow-up, and treatment monitoring of a range of neurological disorders, including multiple sclerosis, amyotrophic lateral sclerosis, and Alzheimer's disease. The marker is increasingly used clinically, as well as in clinical trials. Even if we have validated precise, sensitive, and specific assays for NfL quantification in both cerebrospinal fluid and blood, there are analytical, as well as pre- and post-analytical aspects of the total NfL testing process, including biomarker interpretation, to consider. Although the biomarker is already in use in specialised clinical laboratory settings, a more general use requires some further work. In this review, we provide brief basic information and opinions on NfL as a biomarker of axonal injury in neurological diseases and pinpoint additional work needed to facilitate biomarker implementation in clinical practice.
  •  
10.
  • Arsov, Stefan, et al. (författare)
  • Advanced glycation end-products and skin autofluorescence in end-stage renal disease : a review
  • 2014
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter. - 1434-6621 .- 1437-4331. ; 52:1, SI, s. 11-20
  • Forskningsöversikt (refereegranskat)abstract
    • Chronic kidney disease (CKD), especially in its end stage, is marked by extremely high cardiovascular rates of morbidity and mortality; hemodialysis patients have a five-fold shorter life expectancy than healthy subjects of the same age. In CKD the metabolic products that accumulate in the body are so-called uremic toxins. These include advanced glycation end-products (AGE). AGE levels are markedly increased in CKD patients not only because of impaired excretion but also because of increased production. AGE formation has initially been described as a non-enzymatic reaction between proteins and glucose in the so-called Maillard reaction, but they are also more rapidly formed during oxidative stress and subsequent formation of reactive carbonyl compounds like (methyl) glyoxal. AGE accumulate in tissue where they cross-link with proteins, e. g., collagen, inducing tissue stiffening of blood vessels and skin. They may also interact with receptor of AGE (RAGE) and other receptors, which lead to activation of intracellular transduction mechanisms resulting in cytokine release and further tissue damage in CKD. The accumulation of AGE in the skin can be measured non-invasively using autofluorescence. The skin autofluorescence is a strong marker of cardiovascular mortality in CKD. The focus of this review is on the role of tissue and plasma AGE, and of skin autofluorescence as a proxy of tissue AGE accumulation, in the increase in cardiovascular disease in end stage renal disease (ESRD). This review will also present the possibility of reducing the AGE accumulation in ESRD patients using the following five methods: 1) use of low AGE peritoneal dialysis solutions; 2) use of advanced hemodialysis techniques; 3) use of AGE reducing drugs; 4) optimizing the nutrition of hemodialysis patients; and 5) renal transplantation.
  •  
11.
  •  
12.
  • Ben, Rayana M.C., et al. (författare)
  • Guidelines for sampling, measuring and reporting ionized magnesium in undiluted serum, plasma or blood : International Federation of Clinical Chemistry and Laboratory Medicine (IFCC)
  • 2005
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - 1434-6621 .- 1437-4331. ; 43:5, s. 564-569
  • Tidskriftsartikel (refereegranskat)abstract
    • All analyzers with ion-selective electrodes for ionized magnesium (iMg) should yield comparable and unbiased results. The prerequisite to achieve this goal is to reach consensus on sampling, measurement and reporting. The recommended guidelines for sampling, measurement and reporting iMg in plasma ("plasma" refers to circulating plasma and the forms in which it is sampled: the plasma phase of anticoagulated whole blood, plasma separated from blood cells, or serum) or blood, referring to the substance concentration of iMg in the calibrants, will provide results for iMg that are approximately 3% greater than its true concentration, and 4% less than its true molality. Binding of magnesium to proteins and ligands in plasma and blood is pH-dependent. Therefore, pH should be simultaneously measured to allow adjustment of iMg concentration to pH 7.4. The substance concentration of iMg may be physiologically and consequently clinically more relevant than the substance concentration of total magnesium. © 2005 by Walter de Gruyter.
  •  
13.
  • Ben Rayana, Mohammed C., et al. (författare)
  • IFCC guideline for sampling, measuring and reporting ionized magnesium in plasma
  • 2008
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - 1434-6621 .- 1437-4331. ; 46:1, s. 21-26
  • Tidskriftsartikel (refereegranskat)abstract
    • Analyzers with ion-selective electrodes (ISEs) for ionized magnesium (iMg) should yield comparable and unbiased results for iMg. This IFCC guideline on sampling, measuring and reporting iMg in plasma provides a prerequisite to achieve this goal [in this document, "plasma" refers to circulating plasma and the forms in which it is sampled, namely the plasma phase of anticoagulated whole blood (or "blood"), plasma separated from blood cells, or serum]. The guideline recommends measuring and reporting ionized magnesium as a substance concentration relative to the substance concentration of magnesium in primary aqueous calibrants with magnesium, sodium, and calcium chloride of physiological ionic strength. The recommended name is "the concentration of ionized magnesium in plasma". Based on this guideline, results will be approximately 3% higher than the true substance concentration and 4% lower than the true molality in plasma. Calcium ions interfere with all current magnesium ion-selective electrodes (Mg-ISEs), and thus it is necessary to determine both ions simultaneously in each sample and correct the result for Ca2+ interference. Binding of Mg in plasma is pH-dependent. Therefore, pH should be measured simultaneously with iMg to allow adjustment of the result to pH 7.4. The concentration of iMg in plasma may be physiologically and clinically more relevant than the concentration of total magnesium. Furthermore, blood-gas analyzers or instruments for point-of-care testing are able to measure plasma iMg using whole blood (with intact blood cells) as the sample, minimizing turnaround time compared to serum and plasma, which require removal of blood cells.
  •  
14.
  • Ben Rayana, Mohammed C, et al. (författare)
  • Recommendation for measuring and reporting chloride by ISEs in undiluted serum, plasma or blood
  • 2006
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - 1434-6621 .- 1437-4331. ; 44:3, s. 346-352
  • Tidskriftsartikel (refereegranskat)abstract
    • The proposed recommendation for measuring and reporting chloride in undiluted plasma† or blood by ion-selective electrodes (ISEs) will provide results that are identical to chloride concentrations measured by coulometry for standardized normal plasma or blood samples. It is applicable to all current ISEs dedicated to chloride measurement in undiluted samples that meet the requirements. However, in samples with reduced water concentration, results by coulometry are lower than by ion-selective electrode due to volume displacement. The quantity measured by this standardized ISE procedure is called the ionized chloride concentration. It may be clinically more relevant than the chloride concentration as determined by coulometry, photometry or by ISE after dilution of the sample. © 2006 by Walter de Gruyter.
  •  
15.
  • Bjerke, Maria, 1977, et al. (författare)
  • Assessing the commutability of reference material formats for the harmonization of amyloid beta measurements.
  • 2016
  • Ingår i: Clinical chemistry and laboratory medicine : CCLM / FESCC. - : Walter de Gruyter GmbH. - 1437-4331 .- 1434-6621. ; 54:7, s. 1177-91
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: The cerebrospinal fluid (CSF) amyloid-β (Aβ42) peptide is an important biomarker for Alzheimer's disease (AD). Variability in measured Aβ42 concentrations at different laboratories may be overcome by standardization and establishing traceability to a reference system. Candidate certified reference materials (CRMs) are validated herein for this purpose. METHODS: Commutability of 16 candidate CRM formats was assessed across five CSF Aβ42 immunoassays and one mass spectrometry (MS) method in a set of 48 individual clinical CSF samples. Promising candidate CRM formats (neat CSF and CSF spiked with Aβ42) were identified and subjected to validation across eight (Elecsys, EUROIMMUN, IBL, INNO-BIA AlzBio3, INNOTEST, MSD, Simoa, and Saladax) immunoassays and the MS method in 32 individual CSF samples. Commutability was evaluated by Passing-Bablok regression and the candidate CRM termed commutable when found within the prediction interval (PI). The relative distance to the regression line was assessed. RESULTS: The neat CSF candidate CRM format was commutable for almost all method comparisons, except for the Simoa/MSD, Simoa/MS and MS/IBL where it was found just outside the 95% PI. However, the neat CSF was found within 5% relative distance to the regression line for MS/IBL, between 5% and 10% for Simoa/MS and between 10% and 15% for Simoa/MSD comparisons. CONCLUSIONS: The neat CSF candidate CRM format was commutable for 33 of 36 method comparisons, only one comparison more than expected given the 95% PI acceptance limit. We conclude that the neat CSF candidate CRM can be used for value assignment of the kit calibrators for the different Aβ42 methods.
  •  
16.
  • Björk, Jonas, et al. (författare)
  • Accuracy of GFR estimating equations combining standardized cystatin C and creatinine assays: a cross-sectional study in Sweden
  • 2015
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 53:3, s. 403-414
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The recently established international cystatin C calibrator makes it possible to develop non-laboratory specific glomerular filtration rate (GFR) estimating (eGFR) equations. This study compares the performance of the arithmetic mean of the revised Lund-Malmo creatinine and CAPA cystatin C equations (MEAN(LM-REV+CAPA)), the arithmetic mean of the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) creatinine and cystatin C equations (MEAN(CKD-EPI)), and the composite CKD-EPI equation (CKD-EPICREA+CYSC) with the corresponding single marker equations using internationally standardized calibrators for both cystatin C and creatinine. Methods: The study included 1200 examinations in 1112 adult Swedish patients referred for measurement of GFR (mGFR) 2008-2010 by plasma clearance of iohexol (median 51 mL/min/1.73 m(2)). Bias, precision (interquartile range, IQR) and accuracy (percentage of estimates +/- 30% of mGFR; P-30) were compared. Results: Combined marker equations were unbiased and had higher precision and accuracy than single marker equations. Overall results of MEAN(LM-REV+CAPA)/MEAN(CKD-EPI)/CKD-EPICREA+CYSC were: median bias -2.2%/-0.5%/-1.6%, IQR 9.2/9.2/8.8 mL/min/1.73 m(2), and P-30 91.3%/91.0%/91.1%. The P-30 figures were about 7-14 -percentage points higher than the single marker equations. The combined equations also had a more stable performance across mGFR, age and BMI intervals, generally with P-30 >= 90% and never <80%. Combined equations reached P-30 of 95% when the difference between eGFR(CREA) and eGFR(CYSC) was <10% but decreased to 82% at a difference of >= 40%. Conclusions: Combining cystatin C and creatinine assays improves GFR estimations with P-30 >= 90% in adults. Reporting estimates of both single and combined marker equations in clinical settings makes it possible to assess the validity of the combined equation based on the agreement between the single marker equations.
  •  
17.
  • Björk, Jonas, et al. (författare)
  • GFR estimation based on standardized creatinine and cystatin C : A European multicenter analysis in older adults
  • 2018
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1437-4331 .- 1434-6621. ; 56:3, s. 422-435
  • Tidskriftsartikel (refereegranskat)abstract
    • Although recommended by the Kidney Disease Improving Global Outcomes, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPICR) creatinine equation was not targeted to estimate glomerular filtration rate (eGFR) among older adults. The Berlin Initiative Study (BIS1CR) equation was specifically developed in older adults, and the Lund-Malmö revised (LMRCR) and the Full Age Spectrum (FASCR) equations have shown promising results in older adults. Our aim was to validate these four creatinine equations, including addition of cystatin C in a large multicenter cohort of Europeans ≥70 years. A total of 3226 individuals (2638 with cystatin C) underwent GFR measurement (mGFR; median, 44 mL/min/1.73 m2) using plasma iohexol clearance. Bias, precision (interquartile range [IQR]), accuracy (percent of estimates ±30% of mGFR, P30), eGFR accuracy diagrams and probability diagrams to classify mGFR<45 mL/min/1.73 m2 were compared. The overall results of BIS1CR/CKD-EPICR/FASCR/LMRCR were as follows: median bias, 1.7/3.6/0.6/-0.7 mL/min/1.73 m2; IQR, 11.6/12.3/11.1/10.5 mL/min/1.73 m2; and P30, 77.5%/76.4%/80.9%/83.5% (significantly higher for LMR, p<0.001). Substandard P30 (<75%) was noted for all equations at mGFR<30 mL/min/1.73 m2, and at body mass index values <20 and ≥35 kg/m2. LMRCR had the most stable performance across mGFR subgroups. Only LMRCR and FASCR had a relatively constant small bias across eGFR levels. Probability diagrams exhibited wide eGFR intervals for all equations where mGFR<45 could not be confidently ruled in or out. Adding cystatin C improved P30 accuracy to 85.7/86.8/85.7/88.7 for BIS2CR+CYS/CKD-EPICR+CYS/FASCR+CYS/MEANLMR+CAPA. LMRCR and FASCR seem to be attractive alternatives to CKD-EPICR in estimating GFR by creatinine-based equations in older Europeans. Addition of cystatin C leads to important improvement in estimation performance.
  •  
18.
  • Blennow, Kaj, 1958, et al. (författare)
  • Second-generation Elecsys cerebrospinal fluid immunoassays aid diagnosis of early Alzheimer's disease.
  • 2023
  • Ingår i: Clinical chemistry and laboratory medicine. - : Walter de Gruyter GmbH. - 1437-4331 .- 1434-6621. ; 61:2, s. 234-244
  • Tidskriftsartikel (refereegranskat)abstract
    • Timely diagnosis of Alzheimer's disease (AD) is critical for appropriate treatment/patient management. Cerebrospinal fluid (CSF) biomarker analysis is often used to aid diagnosis. We assessed analytical performance of second-generation (Gen II) Elecsys® CSF immunoassays (Roche Diagnostics International Ltd), and adjusted existing cut-offs, to evaluate their potential utility in clinical routine.Analytical performance was assessed using CSF samples measured with Elecsys CSF Gen II immunoassays on cobas e analyzers. Aβ42 Gen I/Gen II immunoassay method comparisons were performed (Passing-Bablok regression). Cut-off values were adjusted using estimated bias in biomarker levels between BioFINDER protocol aliquots/Gen I immunoassays and Gen II protocol aliquots/immunoassays. Distribution of Gen II immunoassay values was evaluated in AD, mild cognitive impairment (MCI), and cognitively normal cohorts; percentage observations outside the measuring range were derived.The Gen II immunoassays demonstrated good analytical performance, including repeatability, intermediate precision, lot-to-lot agreement (Pearson's r:≥0.999), and platform agreement (Pearson's r:≥0.995). Aβ42 Gen I/Gen II immunoassay measurements were strongly correlated (Pearson's r: 0.985-0.999). Aβ42 Gen II immunoassay cut-offs were adjusted to 1,030 and 800ng/L, and pTau181/Aβ42 ratio cut-offs to 0.023 and 0.029, for Gen II and I protocols, respectively. No observations were below the lower limit of the measuring range; above the upper limit, there were none from the AD cohort, and 2.6 and 6.8% from the MCI and cognitively normal cohorts, respectively.Our findings suggest that the Gen II immunoassays have potential utility in clinical routine to aid diagnosis of AD.
  •  
19.
  • Bonroy, Carolien, et al. (författare)
  • Detection of antinuclear antibodies : recommendations from EFLM, EASI and ICAP
  • 2023
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter. - 1434-6621 .- 1437-4331. ; 61:7, s. 1167-1198
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives: Antinuclear antibodies (ANA) are important for the diagnosis of various autoimmune diseases. ANA are usually detected by indirect immunofluorescence assay (IFA) using HEp-2 cells (HEp-2 IFA). There are many variables influencing HEp-2 IFA results, such as subjective visual reading, serum screening dilution, substrate manufacturing, microscope components and conjugate. Newer developments on ANA testing that offer novel features adopted by some clinical laboratories include automated computer-assisted diagnosis (CAD) systems and solid phase assays (SPA).Methods: A group of experts reviewed current literature and established recommendations on methodological aspects of ANA testing. This process was supported by a two round Delphi exercise. International expert groups that participated in this initiative included (i) the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group “Autoimmunity Testing”; (ii) the European Autoimmune Standardization Initiative (EASI); and (iii) the International Consensus on ANA Patterns (ICAP).Results: In total, 35 recommendations/statements related to (i) ANA testing and reporting by HEp-2 IFA; (ii) HEp-2 IFA methodological aspects including substrate/conjugate selection and the application of CAD systems; (iii) quality assurance; (iv) HEp-2 IFA validation/verification approaches and (v) SPA were formulated. Globally, 95% of all submitted scores in the final Delphi round were above 6 (moderately agree, agree or strongly agree) and 85% above 7 (agree and strongly agree), indicating strong international support for the proposed recommendations.Conclusions: These recommendations are an important step to achieve high quality ANA testing.
  •  
20.
  •  
21.
  • Bäcklund, Nils, et al. (författare)
  • Salivary cortisol and cortisone in diagnosis of Cushing's syndrome - a comparison of six different analytical methods
  • 2023
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter. - 1434-6621 .- 1437-4331. ; 61:10, s. 1780-1791
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives: Salivary cortisol and cortisone at late night and after dexamethasone suppression test (DST) are increasingly used for screening of Cushing's syndrome (CS). We aimed to establish reference intervals for salivary cortisol and cortisone with three liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques and for salivary cortisol with three immunoassays (IAs), and evaluate their diagnostic accuracy for CS.Methods: Salivary samples at 08:00 h, 23:00 h and 08:00 h after a 1-mg DST were collected from a reference population (n=155) and patients with CS (n=22). Sample aliquots were analyzed by three LC-MS/MS and three IA methods. After establishing reference intervals, the upper reference limit (URL) for each method was used to calculate sensitivity and specificity for CS. Diagnostic accuracy was evaluated by comparing ROC curves.Results: URLs for salivary cortisol at 23:00 h were similar for the LC-MS/MS methods (3.4-3.9 nmol/L), but varied between IAs: Roche (5.8 nmol/L), Salimetrics (4.3 nmol/L), Cisbio (21.6 nmol/L). Corresponding URLs after DST were 0.7-1.0, and 2.4, 4.0 and 5.4 nmol/L, respectively. Salivary cortisone URLs were 13.5-16.6 nmol/L at 23:00 h and 3.0-3.5 nmol/L at 08:00 h after DST. All methods had ROC AUCs =0.96.Conclusions: We present robust reference intervals for salivary cortisol and cortisone at 08:00 h, 23:00 h and 08:00 h after DST for several clinically used methods. The similarities between LC-MS/MS methods allows for direct comparison of absolute values. Diagnostic accuracy for CS was high for all salivary cortisol and cortisone LC-MS/MS methods and salivary cortisol IAs evaluated.
  •  
22.
  • Bölenius, Karin, et al. (författare)
  • Minor improvement of venous blood specimen collection practices in primary health care after a large-scale educational intervention
  • 2013
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 51:2, s. 303-310
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Venous blood specimen collection is a common health care practice that has to follow strict guidelines, non-compliance among sampling staff may compromise patient safety. We evaluated a large-scale 2 h educational intervention that emphasised guideline adherence to assess possible improvements of venous blood specimen collection practices.Methods: Blood specimen haemolysis is usually caused by inadequate venous blood specimen collection and handling, reflecting overall pre-analytical handling. We monitored haemolysis of serum samples with haemolysis index corresponding to ≥150 mg/L of free haemoglobin for specimens sent from 11 primary health care centres and analysed on a Vitros 5,1 clinical chemistry analyser before (2008, n=6652 samples) and after (2010, n=6121 samples) the intervention.Results: The total percentage of haemolysed specimens was 11.8% compared to 10.5% (p=0.022) before the intervention. As groups, rural primary health care centres demonstrated a significant reduction [Odds ratios (OR)=0.744] of haemolysed specimens after intervention, whereas urban primary health care centres demonstrated a significant increase (OR=1.451) of haemolysis.Conclusions: A large-scale 2 h educational intervention to make venous blood specimen collection staff comply with guideline practices had minor effects on collection practices. Educational interventions may be effective in wards/care centres demonstrating venous blood specimen collection practices with larger deviations from guidelines.
  •  
23.
  • Börjel, Anna K., et al. (författare)
  • Novel mutations in the 5'-UTR of the FOLR1 gene
  • 2006
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - 1434-6621 .- 1437-4331. ; 44:2, s. 161-167
  • Tidskriftsartikel (refereegranskat)abstract
    • We have previously reported two novel mutations in the 5'-untranslated region (UTR) of the gene for folate receptor-alpha (FOLR1). In our search for additional mutations, 92 patient samples with elevated levels of homocysteine were screened by single-strand conformation polymorphism (SSCP) between nt -425 and -782, and -712 and -1110. Between nt -425 and -782 we did not find any mutations. Between nt -712 and -1110 there were three novel mutations. One subject had two mutations very close to each other, c.-856C>T and c.-921T>C. Two subjects had a c.-1043G>A mutation. To get an idea of the prevalence of FOLR1 mutations in an unselected population, we also screened 692 healthy school children for mutations. In this cohort, between nt -188 and +272 we discovered one novel mutation, a single nucleotide substitution, c.-18C>T, in addition to five children with the 25-bp deletion mutation previously described by us. Thus, so far we have discovered six novel mutations in the 5'-UTR region of the gene for folate receptor-alpha. We genotyped all 17 subjects with a FOLR1 mutation for the methylenetetrahydrofolate reductase (MTHFR) 677C>T polymorphism, and developed new single-nucleotide polymorphism (SNP) genotyping protocols for MTHFR 1298A>C and 1793G>A utilising Pyrosequencing technology. None of the 17 subjects had the 677TT genotype, which ruled out this as a cause of elevated homocysteine levels, which was observed in some of the subjects. Further studies of mutations in the 5'-UTR of FOLR1, and in particular of their interplay with folate intake status, are warranted.
  •  
24.
  • Cadamuro, Janne, et al. (författare)
  • Preanalytical quality improvement - an interdisciplinary journey, on behalf of the European Federation for Clinical Chemistry and Laboratory Medicine (EFLM) Working Group for Preanalytical Phase (WG-PRE)
  • 2022
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter. - 1434-6621 .- 1437-4331. ; 60:5, s. 662-668
  • Tidskriftsartikel (refereegranskat)abstract
    • Since the beginning of laboratory medicine, the main focus was to provide high quality analytics. Over time the importance of the extra-analytical phases and their contribution to the overall quality became evident. However, as the initial preanalytical processes take place outside of the laboratory and mostly without its supervision, all professions participating in these process steps, from test selection to sample collection and transport, need to engage accordingly. Focusing solely on intra-laboratory processes will not be sufficient to achieve the best possible preanalytical quality. The Working Group for the Preanalytical Phase (WG-PRE) of the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) has provided several recommendations, opinion papers and scientific evidence over the past years, aiming to standardize the preanalytical phase across Europe. One of its strategies to reach this goal are educational efforts. As such, the WG-PRE has organized five conferences in the past decade with the sole focus on preanalytical quality. This year's conference mainly aims to depict the views of different professions on preanalytical processes in order to acquire common ground as basis for further improvements. This article summarizes the content of this 6th preanalytical conference.
  •  
25.
  •  
26.
  • Clarin, M., et al. (författare)
  • Detection of subarachnoid haemorrhage with spectrophotometry of cerebrospinal fluid - a comparison of two methods
  • 2022
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 60:7, s. 1053-1057
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives Spectrophotometric absorption curve analysis of cerebrospinal fluid (CSF) for oxyhaemoglobin and bilirubin is necessary to accurately diagnose subarachnoid haemorrhage (SAH) in patients with typical symptoms but with negative findings on X-ray examinations. In this study, we evaluated the performance of two methods for interpreting absorption curves; one method from the United Kingdom National External Quality Assessment Service (UK-NEQAS) and the other from the national quality assurance programme in Sweden (Equalis). Methods Consecutive absorbance curves (n=336) were interpreted with two different methods, and their performance was compared to the diagnosis as stated in the patient records. Results The UK-NEQAS method displayed equal sensitivity to the Equalis method, but the specificity of the UK-NEQAS method was significantly higher than the Equalis method resulting in fewer false positive results. For UK-NEQAS, a positive predictive value (PPV) of 84.6% and a negative predictive value (NPV) of 99.7% were observed, whereas the Equalis method had a PPV of 27.5% and an NPV of 99.7%. Conclusions The semi-automated method based on the guidelines from UK-NEQAS provides an efficient and correct interpretation of absorbance curves with short turn-around times. We propose using this method for the routine interpretation of CSF spectrophotometric curves.
  •  
27.
  • Collinson, P., et al. (författare)
  • Cardiac troponin measurement at the point of care: educational recommendations on analytical and clinical aspects by the IFCC Committee on Clinical Applications of Cardiac Bio-Markers (IFCC C-CB)
  • 2023
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 61:6, s. 989-998
  • Tidskriftsartikel (refereegranskat)abstract
    • The International Federation of Clinical Chemistry and Laboarator Medicine (IFCC) Committee on Clinical Applications of Cardiac Bio-Markers (C-CB) has provided evidence-based educational resources to aid and improve the understanding of important analytical and clinical aspects of cardiac biomarkers. The present IFCC C-CB educational report focuses on recommendations for appropriate use, analytical performance, and gaps in clinical studies related to the use of cardiac troponin (cTn) by point of care (POC) measurement, often referred to as a point of care testing (POCT). The use of high-sensitivity (hs)-cTn POC devices in accelerated diagnostic protocols used in emergency departments or outpatient clinics investigating acute coronary syndrome has the potential for improved efficacy, reduction of length of stay and reduced costs in the health care system. POCT workflow integration includes location of the instrument, assignment of collection and testing responsibility to (non-lab) staff, instrument maintenance, in-service and recurrent training, quality control, proficiency assessments, discrepant result trapping, and troubleshooting and inventory management.
  •  
28.
  • Cornes, Michael, et al. (författare)
  • Order of blood draw : Opinion Paper by the European Federation for Clinical Chemistry and Laboratory Medicine (EFLM) Working Group for the Preanalytical Phase (WG-PRE)
  • 2017
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 55:1, s. 27-31
  • Tidskriftsartikel (refereegranskat)abstract
    • It has been well reported over recent years that most errors within the total testing process occur in the pre-analytical phase (46%-68.2%), an area that is usually outside of the direct control of the laboratory and which includes sample collection (phlebotomy). National and international (WHO, CLSI) guidelines recommend that the order of draw of blood during phlebotomy should be blood culture/sterile tubes, then plain tubes/gel tubes, then tubes containing additives. This prevents contamination of sample tubes with additives from previous tubes that could cause erroneous results. There have been a number of studies recently looking at whether order of draw remains a problem with modern phlebotomy techniques and materials, or it is an outdated practice followed simply because of historical reasons. In the following article, the European Federation of Clinical Chemistry and Laboratory Medicine Working Group for the Preanalytical Phase (EFLM WG-PRE) provides an overview and summary of the literature with regards to order of draw in venous blood collection. Given the evidence presented in this article, the EFLM WG-PRE herein concludes that a significant frequency of sample contamination does occur if order of draw is not followed during blood collection and when performing venipuncture under less than ideal circumstances, thus putting patient safety at risk. Moreover, given that order of draw is not difficult to follow and knowing that ideal phlebotomy conditions and protocols are not always followed or possible, EFLM WG-PRE supports the continued recommendation of ensuring a correct order of draw for venous blood collection.
  •  
29.
  • Damoiseaux, Jan, et al. (författare)
  • An international survey on anti-neutrophil cytoplasmic antibodies (ANCA) testing in daily clinical practice
  • 2018
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter. - 1434-6621 .- 1437-4331. ; 56:10, s. 1759-1770
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Detection of anti-neutrophil cytoplasmic antibodies (ANCA) is important for the diagnosis of the ANCA-associated vasculitides (AAV). For AAV, especially ANCA directed against myeloperoxidase (MPO) and proteinase 3 (PR3) are most relevant. ANCA with less well-defined specificities may, however, also be detected in other inflammatory and non-inflammatory conditions.Methods: A questionnaire, initiated by the European Autoimmunity Standardisation Initiative (EASI), was used to gather information on methods and testing algorithms used for ANCA in clinical laboratories of 12 European countries (EASI survey).Results: Four hundred and twenty-nine responses were included in the EASI survey analysis which revealed differences within countries and between countries. Laboratories overall were poor in adherence to international consensus on ANCA testing. Substantial variation was observed with respect to the use of ANCA indirect immunofluorescence (IIF) in the algorithm, application of distinct methods for MPO- and PR3-ANCA, the daily availability of new ANCA results, and interpretation of test results.Conclusions: Awareness of these differences may stimulate further harmonization and standardization of ANCA testing. This may be promoted by an update of the international ANCA consensus and the introduction of international standards.
  •  
30.
  • Delanaye, Pierre, et al. (författare)
  • Age-adapted percentiles of measured glomerular filtration in healthy individuals : extrapolation to living kidney donors over 65 years.
  • 2022
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter. - 1434-6621 .- 1437-4331. ; 60:3, s. 401-407
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVES: Most data on glomerular filtration rate (GFR) originate from subjects <65 years old, complicating decision-making in elderly living kidney donors. In this retrospective multi-center study, we calculated percentiles of measured GFR (mGFR) in donors <65 years old and extrapolated these to donors ≥65 years old.METHODS: mGFR percentiles were calculated from a development cohort of French/Belgian living kidney donors <65 years (n=1,983), using quantiles modeled as cubic splines (two linear parts joining at 40 years). Percentiles were extrapolated and validated in an internal cohort of donors ≥65 years (n=147, France) and external cohort of donors and healthy subjects ≥65 years (n=329, Germany, Sweden, Norway, France, The Netherlands) by calculating percentages within the extrapolated 5th-95th percentile (P5-P95).RESULTS: Individuals in the development cohort had a higher mGFR (99.9 ± 16.4 vs. 86.4 ± 14 and 82.7 ± 15.5 mL/min/1.73 m2) compared to the individuals in the validation cohorts. In the internal validation cohort, none (0%) had mGFR below the extrapolated P5, 12 (8.2%) above P95 and 135 (91.8%) between P5-P95. In the external validation cohort, five subjects had mGFR below the extrapolated P5 (1.5%), 25 above P95 (7.6%) and 299 (90.9%) between P5-P95.CONCLUSIONS: We demonstrate that extrapolation of mGFR from younger donors is possible and might aid with decision-making in elderly donors.
  •  
31.
  • Dellavance, Alessandra, et al. (författare)
  • Establishment of an international autoantibody reference standard for human anti-DFS70 antibodies : proof-of-concept study for a novel Megapool strategy by pooling individual specific sera
  • 2019
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : WALTER DE GRUYTER GMBH. - 1434-6621 .- 1437-4331. ; 57:11, s. 1754-1763
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: International autoantibody standards, traditionally based on material obtained from plasmapheresis of single subjects, represent individual immune response and may not comprehend the heterogeneity of the general population. The anti-DFS70 autoantibody yields a characteristic dense fine speckled (DFS) nuclear pattern on indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA) and speaks against autoimmunity. We propose a novel strategy for developing autoantibody reference standards, based on stepwise pooling of serum samples from hundreds of individuals with anti-DFS70 antibodies.Methods: Within a 2-year period, serum samples were selected from routine HEp-2 IFA according to the following criteria: DFS HEp-2 IFA pattern at titer >= 1:640; anti-DFS70 reactivity in three analyte-specific tests (Western blot [WB], enzyme-linked immunosorbent assay [ELISA] and chemiluminescent immunoassay [CLIA]). Aliquots of individual samples were combined into progressively larger pools with stepwise validation of intermediary pools as for individual samples. Validated intermediary pools were merged into a final pool for lyophilization.Results: A total of 741 validated samples yielded a 750 mL final pool that was lyophilized into thousands of 200 mu L-aliquots. Reconstituted aliquots yielded the expected anti-DFS70 reactivity in ELISA, CLIA and WB, as well as high-titer DFS HEp-2 IFA pattern. The appropriate antiDFS70 reactivity of the lyophilized pool was confirmed by seven international expert centers, using HEp-2 IFA, ELISA, WB and immunoprecipitation.Conclusions: This proof-of-concept study provides an innovative and efficient strategy to build serum reference standards for autoantibody testing. The anti-DFS70 standard will integrate the panel of standards of Autoantibody Standardization Committee (ASC, www.autoab.org ), contributing to education for proper assay validation and interpretation of the DFS pattern and other HEp-2 IFA patterns.
  •  
32.
  • Diamandis, EP, et al. (författare)
  • Effect of age on serum prostate-specific antigen in women
  • 2017
  • Ingår i: Clinical chemistry and laboratory medicine. - : Walter de Gruyter GmbH. - 1437-4331 .- 1434-6621. ; 55:12, s. E271-E272
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
  •  
33.
  • D'Orazio, P., et al. (författare)
  • Approved IFCC recommendation on reporting results for blood glucose
  • 2006
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - 1434-6621 .- 1437-4331. ; 44:12, s. 1486-1490
  • Tidskriftsartikel (refereegranskat)abstract
    • In current clinical practice, plasma and blood glucose are used interchangeably with a consequent risk of clinical misinterpretation. In human blood, glucose is distributed, like water, between erythrocytes and plasma. The molality of glucose (amount of glucose per unit water mass) is the same throughout the sample, but the concentration is higher in plasma, because the concentration of water and therefore glucose is higher in plasma than in erythrocytes. Different devices for the measurement of glucose may detect and report fundamentally different quantities. Different water concentrations in the calibrator, plasma, and erythrocyte fluid can explain some of the differences. Results for glucose measurements depend on the sample type and on whether the method requires sample dilution or uses biosensors in undiluted samples. If the results are mixed up or used indiscriminately, the differences may exceed the maximum allowable error for glucose determinations for diagnosing and monitoring diabetes mellitus, thus complicating patient treatment. The goal of the International Federation of Clinical Chemistry and Laboratory Medicine, Scientific Division, Working Group on Selective Electrodes and Point of Care Testing (IFCC-SD-WG-SEPOCT) is to reach a global consensus on reporting results. The document recommends reporting the concentration of glucose in plasma (in the unit mmol/L), irrespective of sample type or measurement technique. A constant factor of 1.11 is used to convert concentration in whole blood to the equivalent concentration in plasma. The conversion will provide harmonized results, facilitating the classification and care of patients and leading to fewer therapeutic misjudgments. © 2006 by Walter de Gruyter.
  •  
34.
  • Dragon-Durey, Marie-Agnès, et al. (författare)
  • Repository of intra-and inter-run variations of quantitative autoantibody assays: A European multicenter study
  • 2022
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : De Gruyter Open. - 1434-6621 .- 1437-4331. ; 60:9, s. 1373-1383
  • Tidskriftsartikel (refereegranskat)abstract
    • No reference data are available on repositories to measure precision of autoantibody assays. The scope of this study was to document inter-and intra-run variations of quantitative autoantibody assays based on a real-world large international data set. Members of the European Autoimmunity Standardisation Initiative (EASI) group collected the data of intra-and inter-run variability obtained with assays quantifying 15 different autoantibodies in voluntary participating laboratories from their country. We analyzed the impact on the assay performances of the type of immunoassay, the number of measurements used to calculate the coefficient of variation (CVs), the nature and the autoantibody level of the internal quality control (IQC). Data were obtained from 64 laboratories from 15 European countries between February and October 2021. We analyzed 686 and 1,331 values of intra-and inter-run CVs, respectively. Both CVs were significantly dependent on: The method of immunoassay, the level of IQC with higher imprecision observed when the antibody levels were lower than 2-fold the threshold for positivity, and the nature of the IQC with commercial IQCs having lower CVs than patients-derived IQCs. Our analyses also show that the type of autoantibody has low impact on the assay' performances and that 15 measurements are sufficient to establish reliable intra-and inter-run variations. This study provides for the first time an international repository yielding values of intra-and inter-run variation for quantitative autoantibody assays. These data could be useful for ISO 15189 accreditation requirements and will allow clinical diagnostic laboratories to assure quality of patient results.
  •  
35.
  • Edvardsson, Maria, et al. (författare)
  • Differences in levels of albumin, ALT, AST, gamma-GT and creatinine in frail, moderately healthy and healthy elderly individuals
  • 2018
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : WALTER DE GRUYTER GMBH. - 1434-6621 .- 1437-4331. ; 56:3, s. 471-478
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Reference intervals are widely used as decision tools, providing the physician with information about whether the analyte values indicate ongoing disease process. Reference intervals are generally based on individuals without diagnosed diseases or use of medication, which often excludes elderly. The aim of the study was to assess levels of albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine and gamma-glutamyl transferase (gamma-GT) in frail, moderately healthy and healthy elderly indivuduals. Methods: Blood samples were collected from individuals amp;gt; 80 years old, nursing home residents, in the Elderly in Linkoping Screening Assessment and Nordic Reference Interval Project, a total of 569 individuals. They were divided into three cohorts: frail, moderately healthy and healthy, depending on cognitive and physical function. Albumin, ALT, AST, creatinine and gamma-GT were analyzed using routine methods. Results: Linear regression predicted factors for 34% of the variance in albumin were activities of daily living (ADL), gender, stroke and cancer. ADLs, gender and weight explained 15% of changes in ALT. For AST levels, ADLs, cancer and analgesics explained 5% of changes. Kidney disease, gender, Mini Mental State Examination (MMSE) and chronic obstructive pulmonary disease explained 25% of the variation in creatinine levels and MMSE explained three per cent of gamma-GT variation. Conclusions: Because a group of people are at the same age, they should not be assessed the same way. To interpret results of laboratory tests in elderly is a complex task, where reference intervals are one part, but far from the only one, to take into consideration.
  •  
36.
  • Eggers, Kai M., 1962-, et al. (författare)
  • Differences between high-sensitivity cardiac troponin T and I in stable populations : underlying causes and clinical implications
  • 2023
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter. - 1434-6621 .- 1437-4331. ; 61:3, s. 380-387
  • Tidskriftsartikel (refereegranskat)abstract
    •  ObjectivesMeasurement of high-sensitivity (hs) cardiac troponin (cTn) T and I is widely studied for cardiac assessment of stable populations. Recent data suggest clinical and prognostic discrepancies between both hs-cTn. We aimed at reviewing published studies with respect to underlying causes and clinical implications.ContentWe summarized current evidence on release and clearance mechanisms of cTnT and I, and on preanalytical and assay-related issues potentially portending to differences in measured concentrations. We also performed a systematic review of outcome studies comparing both hs-cTn in the general population, patients with congestive heart failure, stable coronary artery disease and atrial fibrillation.Summary and outlookFor the interpretation of concentrations of hs-cTnT, stronger association with renal dysfunction compared to hs-cTnI should be considered. Hs-cTnT also appears to be a stronger indicator of general cardiovascular morbidity and all-cause mortality. Hs-cTnI concentrations tend to be more sensitive to coronary artery disease and ischemic outcomes. These findings apparently reflect variations in the mechanisms of cardiac affections resulting in cTn release. Whether these differences are of clinically relevance remains to be elucidated. However, having the option of choosing between either hs-cTn might represent an option for framing individualized cardiac assessment in the future.
  •  
37.
  • Eggers, Kai M., 1962-, et al. (författare)
  • Differences between high-sensitivity cardiac troponin T and I in stable populations: underlying causes and clinical implications.
  • 2023
  • Ingår i: Clinical chemistry and laboratory medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 61:3, s. 380-387
  • Tidskriftsartikel (refereegranskat)abstract
    • Measurement of high-sensitivity (hs) cardiac troponin (cTn) T and I is widely studied for cardiac assessment of stable populations. Recent data suggest clinical and prognostic discrepancies between both hs-cTn. We aimed at reviewing published studies with respect to underlying causes and clinical implications.We summarized current evidence on release and clearance mechanisms of cTnT and I, and on preanalytical and assay-related issues potentially portending to differences in measured concentrations. We also performed a systematic review of outcome studies comparing both hs-cTn in the general population, patients with congestive heart failure, stable coronary artery disease and atrial fibrillation.For the interpretation of concentrations of hs-cTnT, stronger association with renal dysfunction compared to hs-cTnI should be considered. Hs-cTnT also appears to be a stronger indicator of general cardiovascular morbidity and all-cause mortality. Hs-cTnI concentrations tend to be more sensitive to coronary artery disease and ischemic outcomes. These findings apparently reflect variations in the mechanisms of cardiac affections resulting in cTn release. Whether these differences are of clinically relevance remains to be elucidated. However, having the option of choosing between either hs-cTn might represent an option for framing individualized cardiac assessment in the future.
  •  
38.
  • Eggers, Kai M., 1962-, et al. (författare)
  • Temporal biomarker concentration patterns during the early course of acute coronary syndrome
  • 2024
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter. - 1434-6621 .- 1437-4331. ; 62:6, s. 1167-1176
  • Tidskriftsartikel (refereegranskat)abstract
    • Objectives: Biomarker concentrations and their changes during acute coronary syndrome (ACS) provide clinically useful information on pathophysiological processes, e.g. myocardial necrosis, hemodynamic stress and inflammation. However, current evidence on temporal biomarker patterns early during ACS is limited, and studies investigating multiple biomarkers are lacking.Methods: We measured concentrations of high-sensitivity cardiac troponin T (hs-cTnT) and I (hs-cTnI), NT-terminal pro-B-type natriuretic peptide, C-reactive protein, and growth-differentiation factor-15 (GDF-15) in plasma samples obtained at randomization in ACS patients from the PLATelet inhibition and patient Outcomes (PLATO) trial. Linear regressions with interaction analyses were used to investigate the associations of biomarker concentrations with the time from symptom onset and to model temporal biomarker concentration patterns.Results: The study population consisted of 16,944 patients (median age 62 years; 71.3 % males) with 6,853 (40.3 %) having ST-elevation myocardial infarction (STEMI) and 10,141 (59.7 %) having non-ST-elevation ACS (NSTE-ACS). Concentrations of all biomarkers were associated with time from symptom onset (pinteraction<0.001), apart for GDF-15 (pinteraction=0.092). Concentration increases were more pronounced in STEMI compared to NSTE-ACS. Temporal biomarker patterns for hs-cTnT and hs-cTnI were different depending on sex whereas biomarker patterns for the other biomarkers were similar in cohorts defined by age and sex.Conclusions: Temporal concentration patterns differ for various biomarkers early during ACS, reflecting the variability in the activation and duration of different pathophysiological processes, and the amount of injured myocardium. Our data emphasize that the time elapsed from symptom onset should be considered for the interpretation of biomarker results in ACS.
  •  
39.
  • Falorni, Alberto, et al. (författare)
  • Determination of 21-hydroxylase autoantibodies: inter-laboratory concordance in the Euradrenal International Serum Exchange Program
  • 2015
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 53:11, s. 1761-1770
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: 21-Hydroxylase autoantibodies (21OHAb) are markers of an adrenal autoimmune process that identifies individuals with autoimmune Addison's disease (AAD). Quality and inter-laboratory agreement of various 21OHAb tests are incompletely known. The objective of the study was to determine inter-laboratory concordance for 21OHAb determinations. Methods: Sixty-nine sera from 51 patients with AAD and 51 sera from 51 healthy subjects were blindly coded by a randomization center and distributed to 14 laboratories that determined 21OHAb, either by an "in-house" assay (n=9) using in vitro-translated S-35-21OH or luciferase-labeled 21OH or a commercial kit with I-125-21OH (n=5). Main outcome measures were diagnostic accuracy of each participating laboratory and inter-laboratory agreement of 21OHAb assays. Results: Intra-assay coefficient of variation ranged from 2.6% to 5.3% for laboratories using the commercial kit and from 5.1% to 23% for laboratories using "in-house" assays. Diagnostic accuracy, expressed as area under ROC curve (AUC), varied from 0.625 to 0.947 with the commercial kit and from 0.562 to 0.978 with "in-house" methods. Cohen's. of inter-rater agreement was 0.603 among all 14 laboratories, 0.691 among "in-house" laboratories, and 0.502 among commercial kit users. Optimized cutoff levels, calculated on the basis of AUCs, increased the diagnostic accuracy of every laboratory (AUC >0.9 for 11/14 laboratories) and increased the Cohen's. of inter-rater agreement. Discrepancies in quantitation of 21OHAb levels among different laboratories increased with increasing autoantibody levels. Conclusions: The quality of 21OHAb analytical procedures is mainly influenced by selection of cutoff value and correct handling of assay materials. A standardization program is needed to identify common standard sera and common measuring units.
  •  
40.
  • Flodin, Mats, et al. (författare)
  • Variations in assay protocol for the Dako cystatin C method may change patient results by 50% without changing the results for controls
  • 2006
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - 1434-6621 .- 1437-4331. ; 44:12, s. 1481-1485
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Cystatin C is increasingly used as a glomerular filtration marker, but so far only a few companies produce most of the cystatin C reagents suited for turbidimetry or nephelometry use in clinical laboratories. Methods: We studied different protocols for measuring cystatin C on an Architect ci8200 system using cystatin C reagents from Dako (Glostrup, Denmark). The results were compared with those obtained with Dade Behring reagents (Deerfield, IL, USA) on a BN ProSpec system. Results: Differences in assay protocol on the same instrument with the Dako reagent yielded an up to 50% difference in glomerular filtration rate calculated from the cystatin C results when analyzing patient samples, but had no effect on the results for controls. There were also significant differences regarding linearity and kinetics between samples and controls/calibrators. Conclusions: The results indicate different reactivity of the Dako antibodies against calibrators and controls in comparison with patient samples, highlighting the importance of using controls and calibrators that do not differ from patient samples.
  •  
41.
  •  
42.
  • Førland, Marthe Gurine, et al. (författare)
  • Validation of a new assay for α-synuclein detection in cerebrospinal fluid.
  • 2017
  • Ingår i: Clinical chemistry and laboratory medicine. - : Walter de Gruyter GmbH. - 1437-4331 .- 1434-6621. ; 55:2, s. 254-260
  • Tidskriftsartikel (refereegranskat)abstract
    • Abnormal α-synuclein aggregation and deposition is the pathological hallmark of Parkinson's disease (PD) and dementia with Lewy bodies (DLB), but is also found in Alzheimer disease (AD). Therefore, there is a gaining interest in α-synuclein in cerebrospinal fluid (CSF) as potential biomarker for these neurodegenerative diseases. To broaden the available choices of α-synuclein measurement in CSF, we developed and validated a new assay for detecting total α-synuclein.
  •  
43.
  • Garcia-Castrillo, Luis, et al. (författare)
  • Recommendations for blood sampling in emergency departments from the European Society for Emergency Medicine (EUSEM), European Society for Emergency Nursing (EuSEN), and European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group for the Preanalytical Phase. Executive summary
  • 2024
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter. - 1434-6621 .- 1437-4331. ; 62:8, s. 1538-1547
  • Tidskriftsartikel (refereegranskat)abstract
    • AIM: Blood Sampling Guidelines have been developed to target European emergency medicine-related professionals involved in the blood sampling process (e.g. physicians, nurses, phlebotomists working in the ED), as well as laboratory physicians and other related professionals. The guidelines population focus on adult patients. The development of these blood sampling guidelines for the ED setting is based on the collaboration of three European scientific societies that have a role to play in the preanalytical phase process: EuSEN, EFLM, and EUSEM. The elaboration of the questions was done using the PICO procedure, literature search and appraisal was based on the GRADE methodology. The final recommendations were reviewed by an international multidisciplinary external review group.RESULTS: The document includes the elaborated recommendations for the selected sixteen questions. Three in pre-sampling, eight regarding sampling, three post-sampling, and two focus on quality assurance. In general, the quality of the evidence is very low, and the strength of the recommendation in all the questions has been rated as weak. The working group in four questions elaborate the recommendations, based mainly on group experience, rating as good practice.CONCLUSIONS: The multidisciplinary working group was considered one of the major contributors to this guideline. The lack of quality information highlights the need for research in this area of the patient care process. The peculiarities of the emergency medical areas need specific considerations to minimise the possibility of errors in the preanalytical phase.
  •  
44.
  • Gellerstedt, Martin, 1966-, et al. (författare)
  • Partitioning reference values for several subpopulations using cluster analysis
  • 2007
  • Ingår i: Clinical chemistry and laboratory medicine. - : Walter de Gruyter. - 1434-6621 .- 1437-4331. ; 45:8, s. 1026-1032
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: A crucial question when developing reference intervals is whether different subpopulations need their own reference interval or if a single joint reference interval can be used. It is reasonable to use partitioned reference intervals in situations where a single interval results in considerable variation in sensitivity between subpopulations. The aim of partitioning is to harmonize the sensitivity of the reference intervals, i.e., to make the sensitivity similar for all patients, regardless of patient characteristics. Statistical criteria to identify when partitioning is adequate have been developed over the last two decades. These criteria are applicable when considering two subpopulations, but recently a procedure for considering several subpopulations has been developed. When several subpopulations are considered, there is a possibility that some subpopulations could form a group or cluster that could share a common reference interval. However, there is no formal systematic approach to indicate how to divide these subpopulations into clusters. The aim of this study was to suggest such a systematic approach for clustering. METHODS: A clustering technique was applied to data including several subpopulations. The technique is based on measuring the distance between separated reference limits and successively pooling subpopulations divided by short distances. A cluster is defined by a group of subpopulations that are close to each other and that differ from subpopulations in another cluster. A cluster recruits new subpopulations as long as the subpopulations can be pooled without violating a partitioning criterion. CONCLUSIONS: We have suggested a procedure for partitioning a number of Gaussian (or Gaussian-transformable) subpopulations into clusters. This is the only formalized procedure indicating how to analyze several subpopulations and identify a suitable number of groups and reference intervals. Using a computer program developed for partitioning issues, the approach was easy to adopt.
  •  
45.
  • Gellerstedt, Martin, 1966- (författare)
  • Partitioning reference values of several Gaussian subpopulations with unequal prevalence--a procedure with computer program support
  • 2006
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - Berlin : Walter de Gruyter. - 1434-6621 .- 1437-4331. ; 44:10, s. 1258-63
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: To be able to interpret laboratory values, it is essential to develop population-based reference intervals. A crucial consideration is whether a reference interval should be divided into subpopulations or not, so-called partitioning. There are established methods for deciding whether partitioning should be done or not. However, these methods are only applicable when partitioning into two subpopulations is considered. The primary aim of this study was to suggest a procedure that was also valid for several subpopulations. The method assumes that these subpopulations are Gaussian. Furthermore, a secondary aim was to provide a tailor-made computer program to support calculations. METHODS: The fundamental idea is to partition reference intervals if the proportions of the distributions of the subpopulations outside the combined reference limit deviate from the nominal value of 0.025. This is made possible by finding the combined reference interval using an equation solver algorithm. RESULTS: It was found that an equation solver algorithm could easily identify the combined reference interval when combining two or more subpopulations, even if these subpopulations had unequal prevalences. It was also found that this could be done even if the ratio between samples does not reflect the ratio between prevalences. Using this algorithm, it was possible to study whether the proportion outside the combined reference limits in any of several subpopulations deviated from the nominal 0.025 by such a magnitude that partitioning was recommended. When similar figures to those found in earlier studies with other methods were tested, the procedure showed consistent results with these methods. The procedure was also found to be applicable when several subpopulations were considered. As a practical result of the study, a tailor-made computer program was developed and is now provided over the Internet. CONCLUSIONS: The suggested procedure could serve as an alternative or complement to existing methods. The procedure provides calculations of the combined reference interval, even if sample fractions do not reflect prevalence fractions. The important advantage with the suggested procedure is the generalisation to the situation when several Gaussian subpopulations, possibly with unequal prevalences, are considered. Finally, since a tailor-made computer program is provided, the procedure is simple to use.
  •  
46.
  • Gobom, Johan, et al. (författare)
  • Validation of the LUMIPULSE automated immunoassay for the measurement of core AD biomarkers in cerebrospinal fluid.
  • 2022
  • Ingår i: Clinical chemistry and laboratory medicine. - : Walter de Gruyter GmbH. - 1437-4331 .- 1434-6621. ; 60:2, s. 207-219
  • Tidskriftsartikel (refereegranskat)abstract
    • The core cerebrospinal fluid (CSF) biomarkers; total tau (tTau), phospho-tau (pTau), amyloid β1-42(Aβ 1-42), and the Aβ 1-42/Aβ 1-40 ratio have transformed Alzheimer's disease (AD) research and are today increasingly used in clinical routine laboratories as diagnostic tools. Fully automated immunoassay instruments with ready-to-use assay kits and calibrators has simplified their analysis and improved reproducibility of measurements. We evaluated the analytical performance of the fully automated immunoassay instrument LUMIPULSE G (Fujirebio) for measurement of the four core AD CSF biomarkers and determined cutpoints for AD diagnosis.Comparison of the LUMIPULSE G assays was performed with the established INNOTEST ELISAs (Fujirebio) for hTau Ag, pTau 181, β-amyloid 1-42, and with V-PLEX Plus Aβ Peptide Panel 1 (6E10) (Meso Scale Discovery) for Aβ 1-42/Aβ 1-40, as well as with a LC-MS reference method for Aβ 1-42. Intra- and inter-laboratory reproducibility was evaluated for all assays. Clinical cutpoints for Aβ 1-42, tTau, and pTau was determined by analysis of three cohorts of clinically diagnosed patients, comprising 651 CSF samples. For the Aβ 1-42/Aβ 1-40 ratio, the cutpoint was determined by mixture model analysis of 2,782 CSF samples.The LUMIPULSE G assays showed strong correlation to all other immunoassays (r>0.93 for all assays). The repeatability (intra-laboratory) CVs ranged between 2.0 and 5.6%, with the highest variation observed for β-amyloid 1-40. The reproducibility (inter-laboratory) CVs ranged between 2.1 and 6.5%, with the highest variation observed for β-amyloid 1-42. The clinical cutpoints for AD were determined to be 409ng/L for total tau, 50.2ng/L for pTau 181, 526ng/L for β-amyloid 1-42, and 0.072 for the Aβ 1-42/Aβ 1-40 ratio.Our results suggest that the LUMIPULSE G assays for the CSF AD biomarkers are fit for purpose in clinical laboratory practice. Further, they corroborate earlier presented reference limits for the biomarkers.
  •  
47.
  • Hammarsten, Ola, et al. (författare)
  • Antibody-mediated interferences affecting cardiac troponin assays: recommendations from the IFCC Committee on Clinical Applications of Cardiac Biomarkers
  • 2023
  • Ingår i: CLINICAL CHEMISTRY AND LABORATORY MEDICINE. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 61:8
  • Tidskriftsartikel (refereegranskat)abstract
    • The International Federation of Clinical Chemistry Committee on Clinical Applications of Cardiac Biomarkers (IFCC C-CB) provides educational documents to facilitate the interpretation and use of cardiac biomarkers in clinical laboratories and practice. Our aim is to improve the understanding of certain key analytical and clinical aspects of cardiac biomarkers and how these may interplay. Measurements of cardiac troponin (cTn) have a prominent place in the clinical work-up of patients with suspected acute coronary syndrome. It is therefore important that clinical laboratories know how to recognize and assess analytical issues. Two emerging analytical issues resulting in falsely high cTn concentrations, often several fold higher than the upper reference limit (URL), are antibody-mediated assay interference due to long-lived cTn-antibody complexes, called macrotroponin, and crosslinking antibodies that are frequently referred to as heterophilic antibodies. We provide an overview of antibody-mediated cTn assay interference and provide recommendations on how to confirm the interference and interpret the results.
  •  
48.
  •  
49.
  •  
50.
  • Helander, Anders, et al. (författare)
  • Toward standardization of carbohydrate-deficient transferrin (CDT) measurements: II. Performance of a laboratory network running the HPLC candidate reference measurement procedure and evaluation of a candidate reference material
  • 2010
  • Ingår i: Clinical Chemistry and Laboratory Medicine. - 1434-6621 .- 1437-4331. ; 48:11, s. 1585-1592
  • Tidskriftsartikel (refereegranskat)abstract
    • Carbohydrate-deficient transferrin (CDT) is a descriptive term used for a temporary change in the transferrin glycosylation profile caused by alcohol, and used as a biomarker of chronic high alcohol consumption. The use of an array of methods for measurement of CDT in various absolute or relative amounts, and sometimes covering different transferrin glycoforms, has complicated the comparability of results and caused confusion among medical staff. This situation prompted initiation of an IFCC Working Group on CDT standardization. This second publication of the WG-CDT covers the establishment of a network of reference laboratories running a high-performance liquid chromatography (HPLC) candidate reference measurement procedure, and evaluation of candidate secondary reference materials. The network laboratories demonstrated good and reproducible performance and thus can be used to assign target values for calibrators and controls. A candidate secondary reference material based on native human serum lyophilized with a cryo-/lyoprotectant to prevent protein denaturation was found to be commutable and stable during storage. A proposed strategy for calibration of different CDT methods is also presented. In an external quality assurance study involving 66 laboratories and covering the current routine CDT assays (HPLC, capillary electrophoresis and immunoassay), recalculation of observed results based on the nominal values for the candidate calibrator reduced the overall coefficient of variation from 18.9% to 5.5%. The logistics for distribution of reference materials and review of results were found to be functional, indicating that a full reference system for CDT may soon be available. Clin Chem Lab Med 2010;48:1585-92.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-50 av 201
Typ av publikation
tidskriftsartikel (188)
forskningsöversikt (8)
konferensbidrag (4)
recension (1)
Typ av innehåll
refereegranskat (183)
övrigt vetenskapligt/konstnärligt (18)
Författare/redaktör
Zetterberg, Henrik, ... (20)
Blennow, Kaj, 1958 (16)
Grankvist, Kjell (14)
Hultberg, Björn (12)
Kallner, A (12)
Larsson, Anders (10)
visa fler...
Theodorsson, Elvar (10)
Andreasson, Ulf, 196 ... (7)
Grubb, Anders (6)
Nilsson, Torbjörn K (6)
Church, Stephen (6)
Hultdin, Johan (6)
Hammarsten, Ola (5)
Damoiseaux, Jan (5)
Lindahl, Bertil, 195 ... (5)
Herold, Manfred (4)
Rönnelid, Johan (4)
Björk, Jonas (4)
Ridefelt, Peter (4)
Gustafson, Lars (4)
Nilsson, Karin (4)
Sandberg, Sverre (4)
Gellerstedt, Martin, ... (4)
Nyman, Ulf (4)
Plebani, Mario (4)
Aakre, K. M. (3)
Collinson, P. (3)
Gil, JP (3)
Ribeiro, V (3)
Yu, A (3)
Portelius, Erik, 197 ... (3)
Bossuyt, Xavier (3)
Fritzler, Marvin J. (3)
Chan, Edward K. L. (3)
Eggers, Kai M., 1962 ... (3)
Lindahl, Bertil (3)
Helander, A (3)
Jonasson, Torfi (3)
Öhlin, Hans (3)
Andrade, Luis E. C. (3)
Satoh, Minoru (3)
Arslan, Burak, 1990 (3)
Kuhle, J. (3)
Mattsson, Niklas, 19 ... (3)
Whitfield, John B. (3)
Helander, Anders (3)
Larsson, Lasse (3)
Eriksson, Catharina, ... (3)
Panteghini, Mauro (3)
Zegers, Ingrid (3)
visa färre...
Lärosäte
Karolinska Institutet (54)
Göteborgs universitet (39)
Lunds universitet (39)
Linköpings universitet (33)
Umeå universitet (32)
Uppsala universitet (32)
visa fler...
Örebro universitet (6)
Högskolan Väst (4)
Högskolan i Skövde (4)
Högskolan Kristianstad (1)
Malmö universitet (1)
visa färre...
Språk
Engelska (201)
Forskningsämne (UKÄ/SCB)
Medicin och hälsovetenskap (125)
Naturvetenskap (10)
Teknik (7)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy