An automated "high-pressure" liquid-chromatographic assay for hemoglobin A1c.

An automated "high-pressure" liquid-chromatographic assay for hemoglobin A1c is described. We use a 45-min incubation in acetate buffer (pH 5.5) to eliminate labile glycated hemoglobins. In this automated system conventional modules are used but it incorporates a solvent-switching valve to select either of two buffers, which differ in pH and NaCl concentration. The chromatographic column contains "polyCAT" (a weak cation-exchanger, polyaspartic acid linked to silica). Run time is 14 min per sample. The method is precise and results correlate well with those by other ion-exchange procedures.