Effects of hemoglobin variants on Hb A1c determinations using Bio-Rad columns

In the column chromatographic determination of Hb A1c, hemoglobin variants affect Hb A1c results and column patterns. Samples from several patients with hemoglobin variants were run on Bio-Rad Hb A1c columns to demonstrate these patterns. Columns should be examined during the run to detect the presence of Hb F which migrates very rapidly, and after the run to detect abnormal column patterns. Hb A1c levels in patients heterozygous for Hb S or C are low but may be interpreted in relation to the patient's level of Hb A. On the other hand, Hb A1c results on patients with homozygous Hb S, Hb C, or high levels of Hb F cannot be interpreted.