This study aimed to analyze and report the results of the 2022 accuracy-based creatinine proficiency testing (ABCr PT) program conducted by the Korean Association of External Quality Assessment Service. The ABCr PT has performed two rounds per year, and three samples of commutable fresh frozen sera were used during each round. In the first round, 1,687 laboratories returned the creatinine test results, and 1,706 in the second round. The results of the estimated glomerular filtration rate (eGFR) were returned by 611 and 624 laboratories, respectively. Among the participant laboratories that responded to eGFR, 24.7%–26.1% of laboratories used the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation to calculate the glomerular filtration rate. The mean percentage bias of the creatinine test, excluding the outliers, ranged from –0.3% to 2.8%. The mean percentage bias of eGFR was –2.8% to 1.5% for CKD-EPI and –1.3% to 2.2% for the Modification of Diet in Renal Disease (MDRD) 4 variable isotopedilution mass spectrometry (IDMS)-traceable equation. The acceptability of the creatinine test was different for each sample, and ranged from 79.4% to 94.4%. The eGFR acceptable rate was 96.7% to 98.8% for CKD-EPI and 96.7% to 99.3% for the MDRD 4 variable (IDMS-traceable).

Keywords: Accuracy, Creatinine, Estimated glomerular filtration rate, Laboratory proficiency testing