Creatinine Measurement: State of the Art in Accuracy and Interlaboratory Harmonization
Open Access
- 1 March 2005
- journal article
- Published by Archives of Pathology and Laboratory Medicine in Archives Of Pathology & Laboratory Medicine
- Vol. 129 (3), 297-304
- https://doi.org/10.5858/2005-129-297-cmsota
Abstract
Context.—The National Kidney Disease Education Program recommends calculating glomerular filtration rate from serum creatinine concentration. Accurate creatinine measurements are necessary for this calculation. Objective.—To evaluate the state of the art in measuring serum creatinine, as well as the ability of a proficiency testing program to measure bias for individual laboratories and method peer groups. Design.—A fresh-frozen, off-the-clot pooled serum specimen plus 4 conventional specimens were sent to participants in the College of American Pathologists Chemistry Survey for assay of creatinine. Creatinine concentrations were assigned by isotope dilution mass spectrometry reference measurement procedures. Participants.—Clinical laboratories with an acceptable result for all 5 survey specimens (n = 5624). Results.—The fresh frozen serum (FFS) specimen had a creatinine concentration of 0.902 mg/dL (79.7 μmol/L). Mean bias for 50 instrument-method peer groups varied from −0.06 to 0.31 mg/dL (−5.3 to 27.4 μmol/L), with 30 (60%) of 50 peer groups having significant bias (P < .001). The bias variability was related to instrument manufacturer (P ≤ .001) rather than method type (P = .02) with 24 (63%) of 38 alkaline picric acid methods and with 6 (50%) of 12 enzymatic methods having significant biases. Two conventional specimens had creatinine concentrations of 0.795 and 2.205 mg/dL (70.3 and 194.9 μmol/L) and had apparent survey biases significantly different (P < .001) from that of the FFS specimen for 34 (68%) and 35 (70%) of 50 peer groups, respectively. Conclusions.—Thirty of 50 peer groups had significant bias for creatinine. Bias was primarily associated with instrument manufacturer, not with type of method used. Proficiency testing using a commutable specimen measured participant bias versus a reference measurement procedure and provided trueness surveillance of instrument-method peer groups.Keywords
This publication has 6 references indexed in Scilit:
- IFCC Reference System for Measurement of Hemoglobin A1c in Human Blood and the National Standardization Schemes in the United States, Japan, and Sweden: A Method-Comparison StudyClinical Chemistry, 2004
- Specimen materials, target values and commutability for external quality assessment (proficiency testing) schemesClinica Chimica Acta; International Journal of Clinical Chemistry, 2003
- Trueness verification in European external quality assessment schemes: time to care about the quality of the samples.Scandinavian Journal of Clinical and Laboratory Investigation, 2003
- Calibration and random variation of the serum creatinine assay as critical elements of using equations to estimate glomerular filtration rateAmerican Journal of Kidney Diseases, 2002
- Assessment of the state-of-the-art trueness and precision of serum total-calcium and glucose measurements in Finnish laboratories - the QSL-Finland studyScandinavian Journal of Clinical and Laboratory Investigation, 1998
- Analytical Reviews in Clinical Biochemistry: The Estimation of CreatinineAnnals of Clinical Biochemistry: International Journal of Laboratory Medicine, 1986