| 1. |
- Aldrimer, Mattias, et al.
(författare)
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Population-based pediatric reference intervals for hematology, iron and transferrin
- 2013
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Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Informa UK Limited. - 0036-5513 .- 1502-7686. ; 73:3, s. 253-261
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Tidskriftsartikel (refereegranskat)abstract
- Reference intervals are crucial decision-making tools aiding clinicians in differentiating between healthy and diseased populations. However, for children such values often are lacking or incomplete. Blood samples were obtained from 689 healthy children, aged 6 months to 18 years, recruited in day care centers and schools. Hematology and anemia analytes were measured on the Siemens Advia 2120 and Abbott Architect ci8200 platforms (hemoglobin, erythrocyte volume fraction [EVF], erythrocytes, mean corpuscular volume [MCV], mean corpuscular hemoglobin [MCH], mean corpuscular hemoglobin concentration [MCHC], reticulocytes, leukocytes, lymphocytes, monocytes, neutrophils, eosinophils, basophils, platelets, iron, transferrin, transferrin saturation). Age-and gender-specific pediatric reference intervals were defined by calculating 2.5th and 97.5th percentiles. The data generated is primarily applicable to a Caucasian population, but could be used by any laboratory if verified for the local patient population.
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| 2. |
- Aldrimer, Mattias, et al.
(författare)
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Reference intervals on the Abbot Architect for serum thyroid hormones, lipids and prolactin in healthy children in a population-based study
- 2012
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Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Informa UK Limited. - 0036-5513 .- 1502-7686. ; 72:4, s. 326-332
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Tidskriftsartikel (refereegranskat)abstract
- Pediatric reference intervals for thyroid hormones, prolactin and lipids are of high clinical importance as deviations might indicate diseases with serious consequences. In general, previous reference intervals are hampered by the inclusion of only hospital-based populations of children and adolescents. The study included 694 children, evenly distributed from 6 months to 18 years of age. They were recruited as volunteers at child care units and schools. All subjects were apparently healthy and a questionnaire on diseases and medications was filled out by parents and by the older children. TSH, free T4, free T3, total cholesterol, LDL, HDL, triglycerides and prolactin were analyzed on Abbott Architect ci8200. Age- and gender-related 2.5 and 97.5 percentiles were estimated. The thyroid hormone levels were similar to previous data for the Abbott Architect platform, but exhibited differences from studies performed with other methods. Prolactin displayed wide reference ranges, but relatively small age-related changes, and a marginal difference between sexes during adolescence. Reference intervals for lipids in the different age groups are known to vary geographically. Levels of LDL and total cholesterol were higher than those reported for children in Canada, but lower than those reported for children in China. The study gives age-and gender-specific pediatric reference intervals, measured with modern methods for a number of important analytes. The results presented here differ from previously recommended reference intervals. In many earlier studies, retrospective hospital-based reference intervals, which may include various sub-groups have been presented. By non-hospital studies it is possible to avoid some of these biases.
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| 3. |
- Brunell, Anna, et al.
(författare)
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Differential diagnostic yield of lumbar puncture in investigation of suspected subarachnoid haemorrhage : a retrospective study
- 2013
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Ingår i: Journal of Neurology. - : Springer Science and Business Media LLC. - 0340-5354 .- 1432-1459. ; 260:6, s. 1631-1636
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Tidskriftsartikel (refereegranskat)abstract
- The diagnostic algorithm of computerized tomography (CT) and lumbar puncture (LP) for suspected subarachnoid haemorrhage (SAH) has lately been challenged by the advancement of radiological techniques, such as higher resolution offered by newer generation CT-scanners and increased availability of CT-angiography. A purely radiological workup of suspected SAH offers great advantages for both patients and the health care system, but the risks of abandoning LP in this setting are not well investigated. We have characterized the differential diagnostic yield of LP in the investigation of suspected SAH by a retrospective study. From the hospital laboratory database, we analyzed the medical records of all patients who had undergone CSF-analysis in search of subarachnoid bleeding during 2009-2011. A total of 453 patients were included. In 14 patients (3 %) the LP resulted in an alternative diagnosis, the most common being aseptic meningitis. Two patients (0.5 %) received treatment for herpes meningitis. Five patients (1 %) with subarachnoid haemorrhages were identified. Among these, the four patients presenting with thunderclap headache had non-aneurysmal bleedings and did not require surgical intervention. We conclude that the differential diagnostic yield of LP in investigation of suspected SAH is low, which indicates that alternative diagnoses is not a reason to keep LP in the workup when a purely radiological strategy has been validated. However, algorithms should be developed to increase the recognition of aseptic meningitis. One hundred and fifty-three patients (34 %) were admitted to undergo LP, which estimates the number of hospital beds that might be made available by a radiological diagnostic algorithm.
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| 4. |
- Ridefelt, Peter, et al.
(författare)
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Alkaline phosphatase in healthy children : reference intervals and prevalence of elevated levels.
- 2014
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Ingår i: Hormone Research in Paediatrics. - : S. Karger AG. - 1663-2818 .- 1663-2826. ; 82:6, s. 399-404
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Transient hyperphosphatasemia (TH) is an often unnoticed benign entity, primarily affecting children below 5 years of age. However, the prevalence among healthy children is unknown. We used data from a Swedish pediatric reference interval project to estimate the prevalence of high alkaline phosphatase (ALP) among healthy children and to calculate pediatric reference intervals.METHODS: Blood was collected from 699 subjectively healthy children aged 6 months to 18 years. After exclusion of subjects with high ALP, age- and gender-specific reference intervals were calculated.RESULTS: Six children had ALP levels >16.7 µkat/l (>1,000 U/l), including 4 females and 2 males aged 7-22 months. The prevalence in the age group from 6 months to 2 years was 6.2% (6/97). None of the older children had levels of ALP >16.7 µkat/l. The study did not include the follow-up of these apparently healthy children. Consequently, conditions others than TH explaining the elevated ALP could not be excluded. However, general chemistry analyses, such as liver enzymes, calcium, intact PTH and vitamin D, were essentially normal in these children.CONCLUSIONS: The prevalence of high ALP among subjectively healthy children was approximately 2.4% below 5 years of age and 6.2% below 2 years. Reference intervals vary with age and gender.
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| 5. |
- Ridefelt, Peter, et al.
(författare)
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Diurnal variability of total calcium during normal sleep and after an acute shift of sleep
- 2012
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Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 50:1, s. 147-151
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Tidskriftsartikel (refereegranskat)abstract
- Background: Serum total calcium is becoming a widely used test when screening for hyperparathyroidism (HPT) and other causes of hypercalcemia, even if serum calcium is tightly regulated in the body it is unclear whether the reference values are correct for tests taken at different times of the day or for individuals with altered sleep patterns. Thus, the aim was to investigate how timing of testing and sleep affects serum calcium. Methods: The diurnal variation of total calcium in serum during night-time and day-time conditions was studied in seven healthy volunteers. Serum samples for calcium measurements were collected every hour (48 samples per individual) to evaluate the effect of sampling times, sleep and food intake on the test results. Results: The median intra-individual coefficients of variations for calcium were 3.3% during night-time sleep and 2.8% during day-time sleep conditions. There was a clear diurnal variation in serum calcium, with a trough at 08.00 h in the morning after night-time sleep and a difference of approximately 0.07 mmol/L between trough and peak. Calcium was lower around the end of the sleep periods, for both night-time and day-time sleep. Food intake did not affect calcium concentrations. Conclusions: Evaluation of serum calcium results should take diurnal variation into account and allow slightly higher calcium values in the afternoon in comparison with samples collected in the morning.
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| 6. |
- Ridefelt, Peter, et al.
(författare)
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Estimating reliable paediatric reference intervals in clinical chemistry and haematology
- 2014
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 103:1, s. 10-15
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Forskningsöversikt (refereegranskat)abstract
- Very few high-quality studies on paediatric reference intervals for general clinical chemistry and haematology analytes have been performed. Three recent prospective community-based projects utilising blood samples from healthy children in Sweden, Denmark and Canada have substantially improved the situation. ConclusionThe present review summarises current reference interval studies for common clinical chemistry and haematology analyses.
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| 7. |
- Ridefelt, Peter, et al.
(författare)
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Increased plasma glucose levels after change of recommendation from NaF to citrate blood collection tubes
- 2014
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Ingår i: Clinical Biochemistry. - : Elsevier BV. - 0009-9120 .- 1873-2933. ; 47:7-8, s. 625-628
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To evaluate changes in plasma glucose measurements in an unselected patient population after a change of recommendation from NaF to citrate blood collection vacuum tubes. Design and methods: Glucose (n = 460 751) and HbA1c (n = 55 190) determinations during a period of approximately three years before and after the tube change were extracted from a laboratory information system. Results: Median values for plasma glucose determinations increased from 6.03 before to 6.28 mmol/L after the tube change. The proportion of glucose determinations above the WHO limit for impaired fasting glucose (6.1 mmol/L) and the medical decision limit for diabetes (7.0 mmol/L) increased from 48.1 to 55.4% after the change. Conclusions: The change from NaF to citrate tubes caused higher glucose values, and consequently more glucose determinations above the decision limit for diabetes.
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| 8. |
- Ridefelt, Peter, 1959-, et al.
(författare)
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Influences of sleep and the circadian rhythm on iron-status indices
- 2010
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Ingår i: Clinical Biochemistry. - : Elsevier BV. - 0009-9120 .- 1873-2933. ; 43:16-17, s. 1323-1328
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The aim was to study the influence of sampling time, food intake and sleep on tests used to screen for and monitor conditions of iron deficiency and overload. Design and methods: The 24 h variations of iron, transferrin, transferrin saturation (TS) and ferritin were studied in seven healthy individuals during standardised food intake, and during night or day sleep. Results: Iron and TS showed clear diurnal variations, with peaks at 12.6 h and 12.8 h respectively, during night sleep, and at 19.7 h and 19.3 h, respectively, during day sleep. Ferritin did not demonstrate any circadian variation. Transferrin and ferritin were unaffected by sleep-condition. Meals did not have any effect except a slight decline of transferrin. Conclusions: Time of day and sleeping patterns had great influence on iron and TS, whereas no or only minor effects are seen on the concentration of ferritin and transferrin. Meals have limited effects. (C) 2010 The Canadian Society of Clinical Chemists.
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