Evaluation for serum glucose standardization in clinical laboratories of Southern China by consecutive 6 years proficiency testing based on JCTLM-recommended reference methods

Abstract Objectives The accuracy of blood glucose measurement in clinical laboratories is vital for diabetes diagnosis. Trueness Verification Plan was carried out and analyzed for evaluating the standardization of serum glucose among clinical laboratories. Methods Trueness verification samples were distributed to clinical laboratories for three days measurement, and their target values were assigned by two certified reference laboratories. The relative bias, coefficient of variation (CV), and total error (TE) for each clinical laboratory were calculated and analyzed. Moreover, the Six Sigma metrics and Quality Goal Index were utilized to reflect the measurement quality of the clinical laboratories. Results The pass rates evaluated by bias, CV, and TE ranged from 45.2 % to 64.8 %, 96.8 %–98.9 %, and 83.9 %–97.1 % over the six years. The matched systems used in clinical laboratories demonstrated better accuracy than the un-matched systems. The pass rate by bias of hexokinase method is 53.1 %–78.6 %, while the glucose oxidase method is 29.2 %–52.2 %. Overall, 74.2 %–85.7 % of clinical laboratories achieved an acceptable level (both σ>3), and 35.2 %–61.4 % of laboratories reached a “world-class” level (both σ>6). Conclusions The quality for serum glucose measurement has been greatly improved. However, standardization among clinical systems still needs to be further promoted.