A comparison of the determination of glucosylated haemoglobin by isoelectric focusing and cation-exchange chromatography on minicolumns

Publisher Website
Google Scholar
Abstract
The labile intermediate, pre A1c, formed in the glycosylation of haemoglobin A is a potential contaminant in the measurement of glycosylated haemoglobin when this is determined as the amount of HbA1c present in the sample. By isoelectric focusing on polyacrylamide gel plates this contamination could be avoided either by excision of the HbA,c leaving the neighbouring pre Alc behind on the slab, or by converting the pre Aic to HbA in glucose-free medium before electrophoresis. In cation-exchange chromatography on minicolumns (from Bio-Rad) the pre Alc was removed in the haemolysis process by borate-induced transformation to the non-interfering HbA. The chromatographic method nevertheless gave about 10% higher values than isoelectric focusing. The linearity between paired results of the electrophoretic and chromatographic methods was not perfect (p>0.05). Both methods measured decreasing concentrations of HbAlc equally well and with the same precision at both high and low levels (CV>5%). All HbF was simultaneously determined in the chromatographic method, while HbF did not interfere in the electrophoretic method. The HbAlc in whole blood samples was stable at 4 °C for up to 1 week. Carbon monoxide treatment made the HbA1c in haemolysates stable for at least 3 months at -70 °C making possible long-term control by both methods.

This publication has 12 references indexed in Scilit: