First report of a rare hemoglobin variant in the Chinese population: clinical and hematological characteristics of Hb Norton [HBA2:c.217C>G] and its impact on HbA1c testing: a case report.
Jian Shang, Zirui Cao, Weidong Chen et al.
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Case in brief
A 38-year-old man presented with a normal clinical and hematological profile but had an unexpectedly high HbA1c level of 20.24% using HPLC. Further testing with capillary electrophoresis and boronate affinity HPLC showed normal values of 5.49% and 5.60%. Analysis confirmed the presence of the rare Hb variant, Hb Norton [HBA2:c.217C>G], which caused the false elevation in HbA1c due to co-elution.
What made this case unusual
This case highlights the first identification of the Hb Norton variant in the Chinese population, which significantly interfered with HbA1c testing.
Diagnostic / clinical pearl
Clinicians should consider the possibility of hemoglobin variants when faced with abnormally high HbA1c results that do not correlate with the clinical picture.
Why it matters
Understanding the impact of rare hemoglobin variants on HbA1c testing is crucial for accurate diabetes management and diagnosis.