Silent haemoglobin variants and determination of HbA1c with the HPLC Bio-Rad Variant II

Aims: To evaluate the determination of HbA1c with an automated high performance liquid chromatography (HPLC) method in patients with clinically silent haemoglobin variants. Methods: HbA1c values were determined with the ion exchange HPL Bio-Rad Variant II using the high resolution β thalassaemia programme in patients with silent haemoglobin variants, namely: Hb Graz, Hb Sherwood Forest, Hb O Padova, and Hb D. Results: All of these haemoglobin variants caused additional peaks in the chromatograms. No clinically useful HbA1c results were produced for patients with Hb Graz and Hb Sherwood Forest, the results for the patient with Hb D were too low, but the results for patients with Hb O Padova were acceptable. Conclusions: The development of this automated HPLC method modification with high resolution mode aids the identification of interference caused by the described clinically silent haemoglobin variants in HbA1c determination.