Why in news?
A recent study published in The Lancet has raised concerns about relying solely on the HbA1c blood test to diagnose diabetes in India. Researchers found that common conditions like anaemia, haemoglobin disorders and genetic enzyme deficiencies can distort HbA1c results, leading to under‑ or over‑diagnosis. The findings have sparked debate over screening strategies in countries with diverse populations.
Background
The HbA1c (glycated haemoglobin) test measures the percentage of haemoglobin that is bound to sugar. It reflects average blood glucose levels over the past two to three months and has become a widely used tool for diagnosing and monitoring diabetes. However, factors that affect red blood cells can skew HbA1c readings. In India, anaemia and certain genetic blood conditions are prevalent, which may make HbA1c less reliable.
Key findings of the study
- Misclassification risk: Relying only on HbA1c could misclassify people’s diabetes status. Some individuals with high blood glucose might appear normal, while others with normal glucose might be diagnosed as diabetic.
- Influence of anaemia and haemoglobinopathies: Conditions such as iron‑deficiency anaemia and thalassemia shorten or lengthen red blood cell life, affecting HbA1c levels independent of blood sugar.
- Geographic variability: The prevalence of anaemia varies across India, so populations in some states may be more affected by HbA1c inaccuracies than others.
Recommendations
- Alternative tests: In low‑resource settings, a combination of oral glucose tolerance tests (OGTT) and self‑monitoring of blood glucose (SMBG) can provide better screening accuracy.
- Combined approaches: In hospitals and clinics, using HbA1c together with OGTT can improve diagnostic sensitivity and specificity.
- Additional markers: For monitoring established diabetes, continuous glucose monitoring and markers like fructosamine (which measures short‑term glycaemic control) may offer complementary information.
Conclusion
While the HbA1c test remains a convenient tool, it is not foolproof in populations with high rates of anaemia and blood disorders. Health workers should be aware of its limitations and use complementary tests to ensure accurate diagnosis and management of diabetes.
Source: Economic Times
