Evaluation of enzymatic BM Test HbA_1c on the JCA-BM6010/C and comparison with Bio-Rad Variant II Turbo, Tosoh HLC 723 G8, and AutoLab immunoturbidimetry assay

Background: A novel enzymatic HbA_1c assay was introduced for use in an automated chemistry analyzer. With this unique method, HbA_1c and plasma glucose can be measured from the same EDTA tube. We evaluated the analytical performance of this enzymatic HbA_1c assay in a JCA-BM6010/C analyzer and compared the HbA_1c values with the results from other widely used methodological instruments. Methods: The imprecision, linearity, carry-over and concordance rate of the enzymatic HbA_1c test (BM Test HbA_1c) using the JCA-BM6010/C analyzer were evaluated. Three hundred and seventy-seven specimens with HbA_1c concentrations from 16 to 133 mmol/mol were used for a comparison study with two high performance liquid chromatography methods: Variant II Turbo and Tosoh HLC 723 G8 and the AutoLab Hemoglobin A_1c immunoturbidimetry reagent using a Hitachi 7600-110. Forty specimens were used for the glucose method comparison. Results: The HbA_1c coefficients of variation of the within-run imprecision for low and high levels were 0.6% and 0.4%, respectively. The linearity of the BM Test HbA_1c using the JCA-BM6010/C analyzer was excellent in the range between 31 mmol/mol and 143 mmol/mol. The carry-over rate was 0.2%. The relationships between the BM test and the other three methods were 0.916×Tosoh G8+3.644, r=0.986; 0.887×Bio-Rad Variant II+1.896, r=0.972; and 0.941×AutoLab+4.532, r=0.977. The concordance rates using a cut-off of 48 mmol/mol were 91.5% with Tosoh G8, 82.8% with Bio-Rad Variant II, and 91.0% with AutoLab. The simultaneously assayed plasma glucose with HbA _1c was 1.002×Routine plasma glucose+0.625, r=1.000 Conclusions: The enzymatic BM Test HbA_1c in the JCA-BM6010/C analyzer showed excellent precision and linearity, and a minimal carry-over rate. The simultaneously assayed plasma glucose analysis showed good performance.