PHG Foundation argues HbA1c genetic variation undermines equitable diabetes diagnosis

A blog post from the PHG Foundation at the University of Cambridge sets out the case for rethinking HbA1c as a universal diagnostic marker for diabetes, pointing to mounting evidence that genetic variants — particularly those affecting haemoglobin structure, red blood cell lifespan, and related traits — can cause HbA1c readings to diverge substantially from true glycaemic status.

The piece draws on research showing that variants more prevalent in people of African, South Asian, and South-East Asian ancestry can produce falsely low or falsely high HbA1c measurements, meaning that diagnostic thresholds developed in predominantly European cohorts may not perform equitably across all populations. The Foundation notes that this has practical implications for how diabetes screening programmes are designed and evaluated, particularly as NHS genomic data infrastructure expands.

The analysis does not recommend specific clinical actions but calls for greater integration of genomic evidence into health technology assessment and guideline development processes, arguing that ignoring the genetic basis of HbA1c variability perpetuates health inequities embedded in current diagnostic frameworks. The post situates the issue within the broader conversation about ancestry-diverse reference datasets and the need for population-representative research.

This is a policy and commentary piece rather than a primary research publication; readers are directed to the underlying literature via the Foundation's blog.