Reliability of Quadruplicated Serological Parameters in the Korean Genome and Epidemiology Study

OBJECTIVES: The aim of this study was to evaluate whether clinical test values from different laboratories in the Korean Genome and Epidemiology Study (KoGES) can be integrated through a statistical adjustment al-gorithm with appropriate intra- and inter-laboratory reliability. METHODS: External quality control data were obtained from the Korean Society for Laboratory Medicine and quadruplicated standardized serological samples (N= 3,200) were manufactured in order to check the in-tra- and inter-laboratory reliability for aspartic acid transaminase (AST), alanine transaminase (ALT), gamma-glutamyl transpeptidase (γ-GTP), blood urea nitrogen (BUN), creatinine, uric acid (UA), fasting blood sugar (FBS), cholesterol, and triglyceride (TG). As an index of inter- and intra-rater reliability, Pearson's correlation coefficient, intraclass correlation coefficients and kappa statistics were estimated. In addition, to detect the po-tential for data integration, we constructed statistical compensation models using linear regression analysis with residual analysis, and presented the R-square values. RESULTS: All correlation coefficient values indicated good intra- and inter-laboratory reliability, which ranged from 0.842 to 1.000. Kappa coefficients were greater than 0.75 (0.75-1.00). All of the regression models based on the trial results had strong R-square values and zero sums of residuals. These results were consistent in the regression models using external quality control data. CONCLUSION: The two laboratories in the KoGES have good intra- and inter-laboratory reliability for ten chemical test values, and data can be integrated through algorithmic statistical adjustment using regression equa-tions.