For Immediate Release: Wednesday, October 21, 2026, 1:30 p.m. U.S. Eastern Time
Media Contact: Evelyn Mantegani, +1 240-833-2014, [email protected]
Presented By: Amy Bentley, PhD, National Human Genome Research Institute (NHGRI)
HbA1c is widely used to screen for abnormal blood glucose and monitor people with type 2 diabetes. However, a study of African populations found that glucose-6-phosphate dehydrogenase, or G6PD, deficiency can substantially lower HbA1c results, potentially causing clinicians to miss abnormal glucose tolerance or mistakenly conclude that diabetes is well controlled.
Researchers examined HbA1c performance among 759 Nigerians and evaluated additional outcomes and alternative biomarkers in 2,555 participants from Ghana, Nigeria, and Kenya. They focused on G6PD deficiency and sickle cell trait, two inherited blood conditions prevalent in West Africa.
G6PD deficiency was associated with HbA1c levels that were 0.7 percentage points lower, despite no association with fasting glucose, fructosamine, or type 2 diabetes. Among participants with G6PD deficiency, HbA1c detected only 14.3% of abnormal glucose tolerance cases, compared with 49% across the full dataset. For diabetes monitoring, HbA1c missed poor glucose control approximately three times more often in those with G6PD deficiency than in those without it. Sickle cell trait had a smaller effect, modestly raising HbA1c and sometimes overclassifying poor control.
Fructosamine, an alternative marker of average blood glucose, performed consistently across genetic subgroups when used for diabetes monitoring. A clinical algorithm combining routine blood measurements also identified likely G6PD deficiency with more than 80% sensitivity and specificity.
The findings suggest that genetic background can affect the accuracy of a cornerstone diabetes test. Locally calibrated HbA1c criteria, targeted G6PD screening, and alternative biomarkers may help reduce missed or misleading results, although further validation is needed before implementation.
About the American Society of Human Genetics (ASHG)
The American Society of Human Genetics (ASHG) is the leading global organization advancing the science of human genetics and genomics. Representing nearly 8,000 researchers, clinicians, genetic counselors, educators, and other professionals, ASHG drives progress in understanding the human genome and its role in health and disease. The Society fosters innovation and collaboration through its flagship events and publications—including the ASHG Annual Meeting and its peer-reviewed journals The American Journal of Human Genetics and Human Genetics and Genomics Advances. ASHG also champions science advocacy, supports the next generation of genetics professionals, and promotes responsible policies and public engagement in genetics. Learn more at www.ashg.org.
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