Variability of Creatinine Measurements in Clinical Laboratories: Results from the CRIC Study
Year: 2010
Type: article
Abstract: OBJECTIVES: Estimating equations using serum creatinine (SCr) are often used to assess glomerular filtration rate (GFR). Such creatinine (Cr)-based formulae may produce biased estimates of GFR when using Cr measurements that have not been calibrated to reference laboratories. In this paper, we sought to examine the degree of this variation in Cr assays in several laboratories associated with academic medical centers affiliated with the Chronic Renal Insufficiency Cohort (CRIC) Study; to consider how best to correct for this variation, and to quantify the impact of such corrections on eligibility for participation in CRIC. Variability of Cr is of particular concern in the conduct of CRIC, a large multicenter study of subjects with chronic renal disease, because eligibility for the study depends on Cr-based assessment of GFR. METHODS: A library of 5 large volume plasma specimens from apheresis patients was assembled, representing levels of plasma Cr from 0.8 to 2.4 mg/dl. Samples from this library were used for measurement of Cr at each of the 14 CRIC laboratories repetitively over time. We used graphical displays and linear regression methods to examine the variability in Cr, and used linear regression to develop calibration equations. We also examined the impact of the various calibration equations on the proportion of subjects screened as potential participants who were actually eligible for the study. RESULTS: There was substantial variability in Cr assays across laboratories and over time. We developed calibration equations for each laboratory; these equations varied substantially among laboratories and somewhat over time in some laboratories. The laboratory site contributed the most to variability (51% of the variance unexplained by the specimen) and variation with time accounted for another 15%. In some laboratories, calibration equations resulted in differences in eligibility for CRIC of as much as 20%. CONCLUSIONS: The substantial variability in SCr assays across laboratories necessitates calibration of SCr measures to a common standard. Failing to do so may substantially affect study eligibility and clinical interpretations when they are determined by Cr-based estimates of GFR.
Source: American Journal of Nephrology
DOI: 10.1159/000296250
Language: English
Subfield: Physiology (medical)
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
Funders: U.S. Department of Veterans Affairs, Cleveland Clinic, Cleveland Clinic Foundation, Johns Hopkins University, Case Western Reserve University, Deutsches Krebsforschungszentrum, Georgia Clinical and Translational Science Alliance, National Institutes of Health, University of Illinois at Urbana-Champaign, University of California, San Francisco, National Institute of Diabetes and Digestive and Kidney Diseases, National Center for Research Resources, National Institute on Minority Health and Health Disparities
Awards: Clinical and Translational Science Institute, G1904494867, G1965526657, G2063336705, G220989761, Case Western Reserve University/Cleveland Clinic CTSA (UL1), G243530825, Institute for Clinical and Translational Research (UL1), Continuation of the Chronic Renal Insufficiency Cohort (CRIC) Study, GENERAL CLINICAL RESEARCH CENTER, General Clinical Research Center, G3815545696, Michigan Institute for Clinical and Health Research (MICHR) (UL1), G56570703, GENERAL CLINICAL RESEARCH CENTER, CKD the metabolic syndrome & cardiovascular illness, General Clinical Research Center, G8676708184, G8738909417, Prospective renal insufficiency cohort evaluation: PRICE, Chronic Renal Insufficiency Cohort (CRIC) Study Clinical Center, Continuation of the University of Illinois Chicago CRIC Clinical Center, Tulane Clinical Center for Chronic Renal Insufficiency Cohort Study, Chronic Renal Insufficiency Cohort Limited competition continuation, Chronic Renal Insufficiency Cohort (CRIC) Study
OpenAlex ID: W2077856938