An appraisal of statistical procedures used in derivation of reference intervals
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Kiyoshi Ichihara
Abstract
When conducting studies to derive reference intervals (RIs), various statistical procedures are commonly applied at each step, from the planning stages to final computation of RIs. Determination of the necessary sample size is an important consideration, and evaluation of at least 400 individuals in each subgroup has been recommended to establish reliable common RIs in multicenter studies. Multiple regression analysis allows identification of the most important factors contributing to variation in test results, while accounting for possible confounding relationships among these factors. Of the various approaches proposed for judging the necessity of partitioning reference values, nested analysis of variance (ANOVA) is the likely method of choice owing to its ability to handle multiple groups and being able to adjust for multiple factors. Box-Cox power transformation often has been used to transform data to a Gaussian distribution for parametric computation of RIs. However, this transformation occasionally fails. Therefore, the non-parametric method based on determination of the 2.5 and 97.5 percentiles following sorting of the data, has been recommended for general use. The performance of the Box-Cox transformation can be improved by introducing an additional parameter representing the origin of transformation. In simulations, the confidence intervals (CIs) of reference limits (RLs) calculated by the parametric method were narrower than those calculated by the non-parametric approach. However, the margin of difference was rather small owing to additional variability in parametrically-determined RLs introduced by estimation of parameters for the Box-Cox transformation. The parametric calculation method may have an advantage over the non-parametric method in allowing identification and exclusion of extreme values during RI computation.
Clin Chem Lab Med 2010;48:1537–51.
©2010 by Walter de Gruyter Berlin New York
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- Editorial
- IFCC Scientific Division
- IFCC Documents
- Nucleic acid reference materials (NARMs): definitions and issues
- An appraisal of statistical procedures used in derivation of reference intervals
- An outline for a vocabulary of nominal properties and examinations – basic and general concepts and associated terms
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- Status Reports
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- Letters to the Editor
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- Congress Abstracts
- 3rd Annual Congress of the Austrian Society for Laboratory Medicine and Clinical Chemistry Salzburg, Austria, 27-30 October 2010
Artikel in diesem Heft
- Editorial
- IFCC Scientific Division
- IFCC Documents
- Nucleic acid reference materials (NARMs): definitions and issues
- An appraisal of statistical procedures used in derivation of reference intervals
- An outline for a vocabulary of nominal properties and examinations – basic and general concepts and associated terms
- Review
- Standardizing plasma protein measurements worldwide: a challenging enterprise
- Status Reports
- Standardization activities in the field of thyroid function tests: a status report
- 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
- Research Articles
- Common reference intervals for aspartate aminotransferase (AST), alanine aminotransferase (ALT) and γ-glutamyl transferase (GGT) in serum: results from an IFCC multicenter study
- Development of a candidate secondary reference procedure (immunoassay based measurement procedure of higher metrological order) for cardiac troponin I: I. Antibody characterization and preliminary validation
- Towards the development of a certified reference material for hemoglobin A2
- Short Communication
- First certified reference material for cystatin C in human serum ERM-DA471/IFCC
- General Clinical Chemistry and Laboratory Medicine
- Increased γ-glutamyltransferase and decreased total bilirubin are associated with metabolic syndrome in Korean postmenopausal women
- Effect of homeostasis model assessment computational method on the definition and associations of insulin resistance
- Association between thyroid hormones, lipids and oxidative stress biomarkers in overt hypothyroidism
- Biochemical markers of particle induced osteolysis in C57BL/6 mice
- An on-line solid phase extraction procedure for the routine quantification of urinary methylmalonic acid by liquid chromatography-tandem mass spectrometry
- Cancer Diagnostics
- Increased integrity of circulating cell-free DNA in plasma of patients with acute leukemia
- The relationship between three heat shock protein 70 gene polymorphisms and susceptibility to lung cancer
- Real-time polymerase chain reaction quantification of free DNA in serum of patients with polyps and colorectal cancers
- Letters to the Editor
- Thyroid hormones are stable even during prolonged frozen storage
- Thyroid hormones after long-term cold storage: stable or unstable, that is the question
- Biomarkers for early detection of mesothelioma in asbestos-exposed subjects
- Mean platelet volume and platelet distribution width are useful in the differential diagnosis of aplastic anemia and idiopathic thrombocytopenic purpura
- Kinetics of highly sensitive troponin I and T after eccentric exercise
- Interferences in red blood cell counting in urinalysis using evacuated tubes
- Congress Abstracts
- 3rd Annual Congress of the Austrian Society for Laboratory Medicine and Clinical Chemistry Salzburg, Austria, 27-30 October 2010
