Measurement of HbA1C: immunoassay vagaries associated with β-globin chain abnormalities

Abstract

From November 2011, in line with the International Expert Committee, New Zealand Society for the Study of Diabetes has recommended the use of HbA1c as the diagnostic test for Diabetes.1 However, HbA1C values can be interfered by the presence of haemoglobinopathies, anaemias and pathological processes which affect the turnover rate of red blood cells.1 Capillarys Flex Piercing-2 measures HbA1C by separating different sub-fractions of haemoglobin according to their different electrophoretic mobility.2 The aim of this study was using values generated by Capillarys as a reference to evaluate the analytical performance of Advia 2400 and Integra 800. Over a period of 7 months a total of 294 EDTA samples with haemoglobinopathies were stored at –80 °C. These samples were run in three batches on Capillarys Flex Piercing, Advia 2400 and Interga 800. Statistical analysis of the data showed the results generated by Integra agree with those of Capillarys, while the results generated by Advia show systematic high bias. Both immunoassays provided results for some of the patients with homozygous β globin chain haemoglobinopathies, while Capillarys did not give any results as these patients do not have any HbA. The clinical significance of these findings is potentially serious. From November 2011, in line with the International Expert Committee, New Zealand Society for the Study of Diabetes has recommended the use of HbA1c as the diagnostic test for Diabetes.1 However, HbA1C values can be interfered by the presence of haemoglobinopathies, anaemias and pathological processes which affect the turnover rate of red blood cells.1 Capillarys Flex Piercing-2 measures HbA1C by separating different sub-fractions of haemoglobin according to their different electrophoretic mobility.2 The aim of this study was using values generated by Capillarys as a reference to evaluate the analytical performance of Advia 2400 and Integra 800. Over a period of 7 months a total of 294 EDTA samples with haemoglobinopathies were stored at –80 °C. These samples were run in three batches on Capillarys Flex Piercing, Advia 2400 and Interga 800. Statistical analysis of the data showed the results generated by Integra agree with those of Capillarys, while the results generated by Advia show systematic high bias. Both immunoassays provided results for some of the patients with homozygous β globin chain haemoglobinopathies, while Capillarys did not give any results as these patients do not have any HbA. The clinical significance of these findings is potentially serious.