Effects of hemoglobin variants HbJ Bangkok, HbE, HbG Taipei, and HbH on analysis of glycated hemoglobin via ion-exchange high-performance liquid chromatography

BackgroundTo explore the effects of HbJ Bangkok, HbE, HbG Taipei, and -thalassemia HbH on the results of HbA1c assessment using ion-exchange high-performance liquid chromatography (IE-HPLC). MethodsWe enrolled five patients in which the results of the IE-HPLC HbA1c assay were inconsistent with the average levels of FBG. We performed hemoglobin capillary (Hb) electrophoresis using whole-blood samples. We also sequenced the genes encoding Hb using dideoxy-mediated chain termination and analyzed HbA1c using borate affinity HPLC (BA-HPLC) and turbidimetric inhibition immunoassay (TINIA). ResultsTwo patients had the HbJ Bangkok variant. Hb genotypes of these patients were (41-42)/(J Bangkok) and (N)/(J Bangkok), and the content of HbJ Bangkok was 93.9% and 52.4%, respectively. The remaining three patients had the following: HbE ((N)/(E) Hb genotype, 23.6% HbE content), HbG Taipei ((N)/(G Taipei) Hb genotype, 39.4% HbG Taipei content), and -thalassemia HbH (6.1% HbH content, 2.8% Hb Bart's content). In the patients with -thalassemia and HbJ Bangkok variants, the presence of the variants interfered with the results of HbA1c analyses using IE-HPLC and TINIA; in the remaining four patients, there was interference with the results of HbA1c IE-HPLC but not with the TINIA assay. There was no interference with BA-HPLC HbA1c results. ConclusionsHbJ Bangkok, HbE, HbG Taipei Hb, and -thalassemia HbH disease cause varying degrees of interference with the analysis of HbA1c using IE-HPLC. In these patients, we suggest using methods free from such interference for the analysis of HbA1c and other indicators to monitor blood glucose levels.