Comparative evaluation of three assay systems for automated determination of hemoglobin A1c.

We evaluated three newly introduced systems for automated determinations of hemoglobin (Hb) A1c, which allow the processing of large amounts of samples in a routine clinical laboratory. We compared these methods--the Variant HPLC, the Hi-Auto A1c analyzer system, and the Roche immunoassay--with the Diamat HPLC system. All showed good precision and good concordance with the Diamat HPLC. The reference range for Hb A1c has to be determined by the laboratory for each assay system. Interference study showed no statistically significant influence of anemia, polycythemia, rheumatoid factor, or chronic hemodialysis, although individual Hb A1c values can be influenced by polycythemia (when measured with the Hi-Auto A1c analyzer) and by chronic hemodialysis (when measured with the Variant HPLC). HPLC was not suitable for measuring Hb A1c in the examined cases of hemoglobin variants; assaying fructosamine seems to be better for monitoring these patients.