| 1. |
|
|
| 2. |
- Rollborn, Niclas, et al.
(author)
-
Good Agreement Between Hba1c Analyzed Using Capillary Electrophoresis, HPLC, Immunological and Enzymatic Methods
- 2019
-
In: Journal of Diabetes, Metabolism and its Complications. ; 1:1, s. 1-7
-
Journal article (peer-reviewed)abstract
- Purpose: Hemoglobin A1c (HbA1c) is an essential marker for assessment of glycemic control in diabetes patients. The aim of this study was to evaluate the agreement between different HbA1c methods.Methodology: We used blood samples to compare HbA1c results analyzed with Capillarys 3 Tera, Roche Tina-Quant HbA1c Gen 3, BioRad Variant II Turbo (3 sites), Mono S® and Abbott Architect enzymatic method. The comparisons were made as paired instrument comparisons with Capillarys 3 Tera.Results: The linear correlations between the HbA1c methods were as follows:Cobas 6000 = 0.982 x Capillarys 3 Tera + 0.975, R² = 0.994;Architect c8000 = 0.982 x Capillarys 3 Tera + 1.064, R² = 0.994; Mono S® = 0.916 x Capillarys 3 Tera + 3.397, R² = 0.965;BioRad Variant II Turbo = 0.923 x Capillarys 3 Tera + 4.062, R² = 0.990; Tosoh G8 = 0.963 x Capillarys 3 Tera + 3.895, R² = 0.996.Conclusions: The different instrument platforms showed the best agreement in the 50-70 mmol/mol interval. Above and below this range the methods separated into 2 groups, one consisting of Capillarys 3 Tera, Roche Tina-Quant and Abbott enzymatic method and the other group consisting of BioRad Variant II Turbo, Tosoh G8 and Mono S®.
|
|
| 3. |
- Björk, Jonas, et al.
(author)
-
Accuracy of GFR estimating equations combining standardized cystatin C and creatinine assays: a cross-sectional study in Sweden
- 2015
-
In: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 53:3, s. 403-414
-
Journal article (peer-reviewed)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.
|
|
| 4. |
- Flodin, Mats, et al.
(author)
-
Evaluation of Dade Behring N Latex Cystatin C reagent on Abbott ci8200
- 2006
-
In: Upsala Journal of Medical Sciences. - 0300-9734 .- 2000-1967. ; 111:2, s. 209-213
-
Journal article (peer-reviewed)abstract
- Plasma cystatin C has been shown in several studies to be superior to plasma creatinine for estimation of glomerular filtration rate (GFR). Reporting cystatin C results in mL/min using conversion formulas for transforming cystatin C expressed as mg/L to GFR expressed as mL/min has greatly facilitated the clinical use of the marker. At our hospital we have an increasing demand for cystatin C and at present we perform over 1,400 cystatin C analyses a month. The test is available at all hours. This in combination with the volume emphasises the need to have the assay close to the routine chemistry instrument to reduce handling time per test and time to report test results. We have thus evaluated the Dade Behring N Latex Cystatin C assay (Dade Behring, Deerfield, IL, USA) on Architect 68200 (Abbott Laboratories, Abbott Park, IL, USA). The nephelometric method on the ProSpec (Dade Behring) and the turbidimetric method on Architect 68200 showed very good agreement (y = 1.0072x + 0.0042; R-2 = 0.987). Accordingly, running the cystatin C analyses on a chemistry instrument (Architect 68200) would be proper to increase the availability of the analysis and reduce turnaround times.
|
|
| 5. |
- Flodin, Mats, et al.
(author)
-
Variations in assay protocol for the Dako cystatin C method may change patient results by 50% without changing the results for controls
- 2006
-
In: Clinical Chemistry and Laboratory Medicine. - 1434-6621 .- 1437-4331. ; 44:12, s. 1481-1485
-
Journal article (peer-reviewed)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.
|
|
| 6. |
- Grubb, Anders, et al.
(author)
-
Generation of a new cystatin C-based estimating equation for glomerular filtration rate by use of 7 assays standardized to the international calibrator
- 2014
-
In: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 60:7, s. 974-986
-
Journal article (peer-reviewed)abstract
- BACKGROUND:Many different cystatin C-based equations exist for estimating glomerular filtration rate. Major reasons for this are the previous lack of an international cystatin C calibrator and the nonequivalence of results from different cystatin C assays.METHODS:Use of the recently introduced certified reference material, ERM-DA471/IFCC, and further work to achieve high agreement and equivalence of 7 commercially available cystatin C assays allowed a substantial decrease of the CV of the assays, as defined by their performance in an external quality assessment for clinical laboratory investigations. By use of 2 of these assays and a population of 4690 subjects, with large subpopulations of children and Asian and Caucasian adults, with their GFR determined by either renal or plasma inulin clearance or plasma iohexol clearance, we attempted to produce a virtually assay-independent simple cystatin C-based equation for estimation of GFR.RESULTS:We developed a simple cystatin C-based equation for estimation of GFR comprising only 2 variables, cystatin C concentration and age. No terms for race and sex are required for optimal diagnostic performance. The equation, [Formula: see text] is also biologically oriented, with 1 term for the theoretical renal clearance of small molecules and 1 constant for extrarenal clearance of cystatin C.CONCLUSIONS:A virtually assay-independent simple cystatin C-based and biologically oriented equation for estimation of GFR, without terms for sex and race, was produced.
|
|
| 7. |
- Gustafsson, Johanna, et al.
(author)
-
Predictors of the first cardiovascular event in patients with systemic lupus erythematosus : a prospective cohort study
- 2009
-
In: Arthritis Research & Therapy. - : Springer Science and Business Media LLC. - 1478-6354 .- 1478-6362. ; 11:6, s. R186-
-
Journal article (peer-reviewed)abstract
- INTRODUCTION :Cardiovascular disease (CVD) is a major cause of premature mortality among Systemic lupus erythematosus (SLE) patients. Many studies have measured and evaluated risk factors for premature subclinical atherosclerosis, but few studies are prospective and few have evaluated risk factors for hard endpoints, i.e. clinically important cardiovascular events (CVE). We investigated the impact of traditional and lupus associated risk factors for the first ever CVE in a longitudinal cohort of SLE patients.METHODS : A total of 182 SLE patients (mean age 43.9 years) selected to be free of CVE were included. Cardiovascular and autoimmune biomarkers were measured on samples collected after overnight fasting at baseline. Clinical information was collected at baseline and at follow up. End point was the first ever CVE (ischemic heart, cerebrovascular or peripheral vascular disease or death due to CVD). Impact of baseline characteristics/biomarkers on the risk of having a first CVE was evaluated with Cox regression.RESULTS :Follow up was 99.5% after a mean time of 8.3 years. Twenty-four patients (13%) had a first CVE. In age-adjusted Cox regression, any positive antiphospholipid antibody (aPL), elevated markers of endothelial activation (von Willebrand factor (vWf), soluble vascular cellular adhesion molecule-1 (sVCAM-1)) and fibrinogen predicted CVEs. Of SLE manifestations, arthritis, pleuritis and previous venous occlusion were positively associated with future CVEs while thrombocytopenia was negatively associated. Among traditional risk factors only age and smoking were significant predictors. In a multivariable Cox regression model age, any positive aPL, vWf and absence of thrombocytopenia were all predictors of the first CVE.CONCLUSIONS : In addition to age, positive aPL, biomarkers indicating increased endothelial cell activity/damage, and absence of thrombocytopenia were independent predictors of CVEs in this prospective study. Our results indicate that activation of the endothelium and the coagulation system are important features in SLE related CVD. Furthermore, we observed that the risk of CVEs seems to differ between subgroups of SLE patients.
|
|
| 8. |
- Gustafsson, Johanna, et al.
(author)
-
Risk factors for cardiovascular mortality in patients with systemic lupus erythematosus, a prospective cohort study
- 2012
-
In: Arthritis Research & Therapy. - : Springer Science and Business Media LLC. - 1478-6354 .- 1478-6362. ; 14:2, s. R46-
-
Journal article (peer-reviewed)abstract
- INTRODUCTION:Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease. Cardiovascular disease (CVD) is common and a major cause of mortality. Studies on cardiovascular morbidity are abundant, whereas mortality studies focusing on cardiovascular outcomes are scarce. The aim of this study was to investigate causes of death and baseline predictors of overall (OM), non-vascular (N-VM), and specifically cardiovascular (CVM) mortality in SLE, and to evaluate Systematic coronary risk evaluation (SCORE).METHODS:208 SLE patients were included 1995-1999 and followed up after 12 years. Clinical evaluation, CVD risk factors, and biomarkers were recorded at inclusion. Death certificates and autopsy protocols were collected. Causes of death were divided into CVM (ischemic vascular and general atherosclerotic diseases), N-VM and death due to pulmonary hypertension. Predictors of mortality were investigated using multivariable Cox regression. SCORE and standardized mortality ratio (SMR) were calculated.RESULTS: During follow-up 42 patients died at mean age of 62 years. SMR 2.4 (CI 1.7-3.0). 48% of deaths were caused by CVM. SCORE underestimated CVM but not to a significant level. Age, high cystatin C levels and established arterial disease were the strongest predictors for all- cause mortality. After adjusting for these in multivariable analyses, only smoking of traditional risk factors, high soluble vascular cell adhesion molecule-1 (sVCAM-1), high sensitivity C-reactive protein (hsCRP), anti-beta2 glycoprotein-1 (abeta2GP1) and any antiphospholipid antibody (aPL) among biomarkers, remained predictive of CVM.CONCLUSION:With the exception of smoking, traditional risk factors do not capture the main underlying risk factors for CVM in SLE. Rather, cystatin C levels, inflammatory and endothelial markers, and anticardiolipin antibodies (aCL) differentiate patients with favorable versus severe cardiovascular prognosis. Our results suggest that these new biomarkers are useful in evaluating the future risk of cardiovascular mortality in SLE patients.
|
|
| 9. |
- Hallberg, Pär, et al.
(author)
-
Cystatin C vs creatinine as markers of renal function in patients on digoxin treatment
- 2004
-
In: Upsala Journal of Medical Sciences. - 0300-9734 .- 2000-1967. ; 109:3, s. 247-253
-
Journal article (other academic/artistic)abstract
- BACKGROUND: The kidney function is a major determinant of the serum concentration of digoxin as this drug is mainly eliminated unchanged through the kidneys. Since digoxin is widely prescribed among the elderly, and the glomerular filtration rate (GFR) declines with age, it is important that the clinician takes the patient's GFR into account when prescribing digoxin. Serum cystatin C has been suggested to be superior to creatinine for estimation of GFR, which may have relevance for the optimization of treatment with digoxin. METHODS: To evaluate which of the two GFR markers serum creatinine and serum cystatin C that best correlates with serum digoxin, we compared the serum levels of digoxin with the serum levels of creatinine and cystatin C in 149 patients on therapeutic drug monitoring of digoxin at our hospital. RESULTS: Overall, there was a stronger correlation between serum digoxin concentrations and cystatin C (p=0.00001) as compared to creatinine (p= 0.00003). Interestingly, of the patients with a serum digoxin concentration > or = 1.5 nmol/L, 29% had a serum creatinine level within normal limits, as compared to 20% with normal cystatin C levels. CONCLUSIONS: In this study, serum cystatin C correlated better to serum digoxin than did serum creatinine. With improved GFR monitoring, digoxin concentrations should be better controlled.
|
|
| 10. |
- Hansson, Lars-Olof, et al.
(author)
-
Comparison between Chicken and Rabbit Antibody Based Particle Enhanced Cystatin C Reagents for Immunoturbidimetry
- 2008
-
In: Journal of immunoassay & immunochemistry. - : Informa UK Limited. - 1532-1819 .- 1532-4230. ; 29:1, s. 1-9
-
Journal article (peer-reviewed)abstract
- We have compared three commercial particle enhanced cystatin C reagents. One of the reagents utilizes chicken antibodies and the other two reagents are rabbit antibody based. We show that the chicken antibody based reagent yields a higher delta absorbance when reacting with the antigen. IgY coupled to latex particles show a strong scatter response even at high antigen concentrations in contrast to the steep decline in scatter previously reported for IgY antibodies in solution. The reagent also showed a low CV for duplicate samples. Laying hens thus seems as an interesting source of antibodies for particle-enhanced immunoassays.
|
|
