Evaluation of Analytical Performance of the D-100 Hemoglobin Testing System for Hemoglobin A1c Assay

ABSTRACT

BACKGROUND: The hemoglobin A1c (HbA1c) level is widely used to diagnose and monitor glycaemic control in people with diabetes mellitus, and various methods are used for its determination. The D-100 hemoglobin testing system (Bio-Rad Laboratories, USA) is a fully automated, high-throughput glycohaemoglobin analyzer based on an ion-exchange high-performance liquid chromatographic method. Here, we evaluated the analytical performance of a newly developed HbA1c analyzer. METHODS: Precision, linearity, and comparison to the Variant II Turbo analyzer (Bio-Rad Laboratories, USA) were evaluated according to the Clinical Laboratory Standards Institute guidelines. Carryover, bias from the value assigned by the HbA1c Network Laboratory of Korea Centers for Disease Control and Prevention, and the vulnerability to interference by hemoglobin variants frequently found in Korea were also assessed. Statistical analyses were performed using Excel 2010 (Microsoft Co., USA) and MedCalc ver. 14.12.0 (MedCalc Software bvba, Belgium). RESULTS: The coefficients of variation for repeatability and within-device precision were less than 1.08% in National Glycohaemoglobin Standardization Program (NGSP) unit and less than 1.68% in international system of unit at all three levels. The calibration curve was linear, with R²=0.996 in the range of 4.6% to 15.4% in NGSP unit. The results highly correlated with those produced by Variant II Turbo (r=0.998). The 95% confidence interval for differences from the assigned values was -3.3% to 2.9%. No significant interferences of haemoglobin variants were observed except for Hemoglobin Yamagata. CONCLUSIONS: The D-100 hemoglobin testing system showed excellent precision, linearity, and good correlation with the Variant II Turbo analyzer and agreement with the assigned values. Therefore, its analytical performance is satisfactory for diabetes diagnosis and treatment monitoring.