The methods of HbA1c assay using ion exchange high pressure liquid chromatography (HPLC) allow the detection of the most common hemoglobin variants. This observation highlights the different behaviour of two HPLC analyzers in the presence of Tatras hemoglobin. By one of the analyzer (Variant II, Bio-Rad) this variant is detected, but not by the other (G8, Tosoh Biosciences). As HbA1c result is crucial for the therapeutic decision, it is important that biologists know the characteristics of the method they use, in order to detect the possible occurence of an hemoglobinopathy and to ensure the best interpretation of the result.