Hemoglobin Fukuoka caused unexpected hemoglobin A_1c results: A case report

Glycated hemoglobin (Hb) (HbA_1c) is an indicator that is used to diagnose and monitor the treatment of diabetes. Many factors can affect the detection of HbA_1c. One of the most important of these factors is the Hb variant. Here, we report a rare Hb variant and evaluate its effect on HbA_1c.

A 35-year-old man was suspected of harboring an Hb variant following the measurement of HbA_1c with the Variant II Turbo 2.0 Hb detection system during a routine examination. Subsequently, we used the Arkray HA-8160 and ARCHITECT c4000 system to reanalyze HbA_1c. Finally, the Hb variant was detected with a Capillary2FP analyzer that operates on the principle of capillary electrophoresis. We also used gene sequencing to investigate the mutation site. The value of HbA_1c detected with the Variant II Turbo 2.0 system was 52.7%. However, the Arkray HA-8160 system did not display a result while the ARCHITECT c16000 system showed a result of 5.4%. The Capillary2FP analyzer did not reveal any abnormal Hb zones. However, gene sequencing identified the presence of a mutation in the Hb β2 chain [CD2(CAC>TAC), His>Tyr, HBB: c.7C>T]; the genotype was Hb Fukuoka.

Hb variants could cause abnormal HbA_1c results. For patients with Hb variants, different methods should be used to detect HbA_1c.