Falsely high glycated haemoglobin [HbA1C] because of haemoglobin OSU-Christiansborg

Abstract

Glycated haemoglobin (HbA1c) is routinely used to assess the degree of glycaemic control in diabetic patients. We report a case of a 73 year old diabetic woman who had an elevated HbA1c of 13.4%. She was on maximum oral hypoglycaemic agents and was commenced on insulin. However, her HbA1c continued to remain high at 20.4%. Subsequent tests revealed that she had a haemoglobin variant, Haemoglobin Osu-Christiansborg, causing the falsely high glycated haemoglobin.

Factitious Biochemical Measurements Resulting From Hematologic Conditions

“…However, HbA 1c measurement by highperformance liquid chromatography (HPLC)-based assays is inaccurate in the presence of some structurally abnormal hemoglobins. 63,70,71,[77][78][79]87,88 The extent of interference varies with the specific commercial HPLC method used and the type of abnormal hemoglobin.…”

“…70 Other variants result in overestimation of HbA 1c , eg, Hb Raleigh, 80 Hb Okayama, 70 Hb Graz, 63 HbK Woolwich, 77 Hb Osu-Christiansborg, 78 Hb Sherwood Forest, Hb South Florida, and Hb Niigata. Increased HbF, eg, in hereditary persistence of fetal hemoglobin or the rise of HbF during pregnancy may also yield factitiously higher results for HbA 1c because of coelution.…”