Interference and disposition of hemoglobin variants on HbA1c testing results

Abstract

Objective To analyze the causes of the HbA1c results discordant with blood glucose measurements, evaluate the interference degree of hemoglobin variants on the HbA1c results achieved by the method of ion exchange high performance liquid chromatography (IE-HPLC), and discuss the measures should be taken by the lab. Methods Four cases with inconsistency between the results of HbA1c with IE-HPLC method and those of blood glucose were collected. The dideoxy chain termination method was used for hemoglobin gene sequencing and immunoturbidimetric method (TINIA method) for detection of HbA1c. Hemoglobin electrophoresis analysis of whole blood samples was conducted with hemoglobin capillary electrophoresis method. Results There were 2 patients with Hb J-Bangkok .The genotypes were β41-42/βJ-Bangkok and βN/βJ-Bangkok, the accounts of Hb J-Bangkok were 93.9% and 52.4%, respectively.Three was one patient with Hb E.The genotype was βN/βE, the accounts of Hb E was 23.6%.There was one patient with Hb G-Taipei.The genotype was βN/βG-Taipei, the accounts of Hb G-Taipei was 39.4%. In the Hb J-Bangkok patients, the interferences of HbA1c results were found in both IE-HPLC method and TINIA method. In the rest 2 patients, the interferences were found in IE-HPLC method, but not in TINIA method. Conclusions β-thalassemia combined with hemoglobin variants including Hb J-Bangkok, Hb J-Bangkok, Hb E and Hb G-Taipei has interference to varying degrees on the detection of HbA1c with IE-HPLC. In these cases, the lab should use other methods not affected by Hb variants for HbA1c detection or alternative indicators to monitor glucose levels. （Chin J Lab Med,2014,37:123-126） Key words: Hemoglobin A, Glycosylated; Hemoglobins; Variation (genetics); Chromatography, high pressure liquid