To the Editor: The presence of hemoglobin variants can cause interferences with some Hemoglobin A1c (Hb A1c)1 methods. Boronate affinity chromatography is often used as the comparative method for hemoglobin interference studies, as it is generally assumed to be unaffected by most hemoglobin variants since total glycohemoglobin is measured regardless of hemoglobin species. We previously validated the use of the Trinity Biotech ultra2 boronate affinity HPLC as a comparative method for assessing interference from HbS and HbC traits (1). Here, we validate the use of the ultra2 as a comparative method for HbE trait (HbAE) and HbD-Punjab trait (HbAD) interference studies by comparing ultra2 Hb A1c results from samples with these variants with those of the IFCC HPLC–capillary electrophoresis (CE) reference method for Hb A1c (IFCC RM). The IFCC RM measures the β chain N-terminal glycated and nonglycated hexapeptides after a proteolytic digestion (2). Since the …