QUANTITATIVE MEASUREMENT OF HBA(1C) BY AN IMMUNOTURBIDIMETRIC ASSAY COMPARED TO A STANDARD HPLC METHOD

Determination of hemoglobin A1c (HbA(1c)) is one of the most important monitoring procedures for long-term control of diabetes mellitus. Several analytical methods have been developed for the measurement of glycohemoglobin (GHb). Those most frequently used are ion-exchange chromatography for HbA(1c) and affinity chromatography for total GHb. In this study, a new turbidimetric immunoassay for HbA(1c) (Boehringer Mannheim, Germany) was evaluated that was performed on a Hitachi 911 clinical chemistry analyzer (Boehringer Mannheim). Good linearity in the range of 5% to 15% HbA(1c) within-run and between-run coefficients of variation ranging from 2.4% to 5.9% were obtained. Results of 179 diabetic and nondiabetic patients showed good correlation to those of a routine HPLC method (r = 0.96). In addition, HbA2, HbS, and HbF in samples from nondiabetic patients were not detected by the immunoturbimetric assay and the ''labile'' HbA(1c) fraction (Schiff base) did not interfere with the new test.