The effects of abnormal hemoglobins on a new microcolumn method to determine hemoglobin A1c

A new cation-exchange microcolumn employing a borate buffer reportedly separates hemoglobin A1c from other labile glycosylated intermediates in a one step procedure. The effect of commonly occurring abnormal hemoglobins on the hemoglobin A1c (Hb A1c) levels as determined by this new technique has been studied and compared to the values obtained by isoelectric focusing. If a patient has hemoglobin levels in the normal range, or if HbS, HbE, or an elevated HbA2 are present, then hemoglobin A1c levels as estimated by this new column are unaffected or decreased. However, if HbF is elevated, a marked increase in the HbA1c level is observed. The increase is almost directly proportional to the HbF level up to 40 percent. This new column technique is therefore useful in eliminating labile glycosylated hemoglobin intermediates but must be coupled with other techniques if high HbF values are present.