A-093 Study of Hemoglobin Variants Interference to Enzymatic HbA1c Assay on Mindray BS-2800M Analyzer

Abstract Background HbA1c reflects the average blood glucose level during the preceding 2 to 3 months. It is an important analyte for screening and diagnosing diabetes, and monitoring the diabetes progression. Hemoglobin variants are common interference factors for the HbA1c assay. This study aims to assess the analytical performance of Mindray enzymatic assay for HbA1c measurement on Mindray BS-2800M autoanalyzer, and also, in particular, to evaluate the measurement accurate in the presence of interference of hemoglobin variants (HbE, Hb NewYork, Hb G, Hb G-Honolulu, and Hb Q-Thailand) by four commonly used methods for measuring HbA1c in clinical laboratories. Methods Analytical performance evaluation included precision and accuracy. Total precision was assessed according to the Clinical and Laboratory Standards Institute (CLSI) EP05-A2 guidelines by using quality control materials and fresh whole blood samples, 8 samples from IFCC was assessed for accuracy. The sigma metric for HbA1c was calculated using the formula s=(TEa-|bias|)/CV. Furthermore, a large number (n=156) of 5 different hemoglobin variants samples were collected and HbA1c results was compared between enzymatic method (Mindray BS-2800M), cation-exchange high-performance liquid chromatography (HPLC) method (D-100), capillary electrophoresis method (Capillarys 3 TERA, C3), boronate affinity method (Premier Hb9210). Results When calculated in NGSP units and sample concentrations ranged from 4.9% to 10.2%, the coefficients of variation (CV) for total precision were between 0.31% to 0.51%. The results of enzymatic assay of whole blood samples of glycosylated hemoglobin assigned by IFCC calibrators were correlated with their target values with slope of 0.998, and the relative biases were all within ±5%. 6.0% was used as the total allowable error for HbA1c, sigma metrics of HbA1c measured by enzymatic assay varied from 11.99 to 19.49 with “world class” quality while sample concentrations ranged from 4.9% to 10.2%. A total of 5 hemoglobin variants types were identified in 156 patients. The most common variant was Hb E(n=85), followed by Hb G(n=30), Hb Q-Thailand (n=17), Hb NewYork (n=12), Hb G-Honolulu(n=12). Mindray enzymatic assay showed great correlation and agreement with D-100,C3,Hb9210. The correlation coefficients were greater than 0.96 and the relative deviations were within 10%? Conclusion Enzymatic HbA1c assay is an economical, efficient and accurate detection method, which shows good anti-interference capability from hemoglobin variants (HbE, Hb NewYork, Hb G, HB G-Honolulu, and Hb Q-Thailand) and can provide accurate HbA1c results for clinical laboratories. It is suitable for routine use in large, medium, and small clinical laboratories.