Usefulness of HbA1c Measurements by HPLC- and Immuno-Assay for Screening Unstable Hemoglobinopathy.

Unstable hemoglobinopathy (UH), red blood cell membrane disease (MD), and red blood cell enzymopathy are known as major congenital hemolytic anemias. Specialized examinations are needed for their differential diagnosis. We hypothesized that simultaneous measurements of HbA1c levels using high-performance liquid chromatography (HPLC) by fast mode (FM) and immunoassay [HPLC (FM)-HbA1c and IA-HbA1c, respectively] are useful for the differential diagnosis of UH from other congenital hemolytic anemias and verified this hypothesis in this study.HPLC (FM)-HbA1c and IA-HbA1c levels were simultaneously measured in 5 variant hemoglobinopathy (VH) patients with β-chain heterozygous mutation, 8 MD patients, 6 UH patients, and 10 healthy controls. None of the patients had diabetes mellitus.In VH patients, HPLC-HbA1c levels were low, whereas IA-HbA1c levels were within the reference range. In MD patients, HPLC-HbA1c and IA-HbA1c levels were similarly low. In UH patients, both HPLC-HbA1c and IA-HbA1c levels were low, but HPLC-HbA1c levels were significantly lower than IA-HbA1c levels. The HPLC-HbA1c/IA-HbA1c ratio was 90% or more in all MD patients and control subjects. This ratio was, however, less than 90% in all VH patients and UH patients.The HPLC (FM)-HbA1c/IA-HbA1c ratio calculated using simultaneous measurements of HPLC (FM)-HbA1c and IA-HbA1c levels is useful for the differential diagnosis of VH, MD, and UH.