Hb Okayama is a rare variant of human haemoglobin first identified in Japan. It results from a single amino acid substitution in the β-globin chain, causing a minor structural change that is typically not associated with significant clinical symptoms.
While most carriers are asymptomatic or present only mild anaemia, Hb Okayama has particular importance in laboratory diagnostics, especially in HbA1c testing. Certain analytical methods may fail to accurately identify this variant, potentially leading to erroneous HbA1c results and misinterpretation of glycaemic control.
This case highlights the value of HPLC-based HbA1c analysis, which can clearly separate haemoglobin fractions, detect abnormal peaks, and identify variants such as Hb Okayama through chromatogram review. In this variant, co-migration with the HbA1c fraction may occur, making chromatographic interpretation essential.
HbA1c is more than just a numerical result. The ability to detect haemoglobin variants and interpret chromatographic flags is crucial for ensuring accurate patient assessment and reliable diabetes management.