HbA1c May Not Reliably Reflect Blood Sugar Levels in Many Indians: Lancet Viewpoint - Video

A new evidence-based viewpoint published in The Lancet Regional Health: Southeast Asia has raised concerns about the reliability of the widely used glycated hemoglobin (HbA1c) test for diagnosing and monitoring type 2 diabetes in India. The review suggests that in populations with high rates of anemia, hemoglobinopathies, and G6PD deficiency, HbA1c levels may not accurately reflect average blood glucose.

HbA1c measures the glycation of hemoglobin and is commonly used to assess long-term blood sugar control. However, any condition that affects the quantity, structure, or lifespan of red blood cells can distort HbA1c readings. In India, where iron deficiency anemia and inherited blood disorders are prevalent in several regions, this limitation could affect millions.

Co-author Dr. Shashank Joshi from Mumbai highlighted that even in advanced urban hospitals, HbA1c results can be influenced by red blood cell variations. In rural and tribal regions, where anemia and genetic blood disorders are more common, discrepancies may be greater.

The review warns that sole reliance on HbA1c could delay diabetes diagnosis by up to four years in men with undetected G6PD deficiency, potentially increasing the risk of complications.

India currently has over 100 million people living with diabetes, with many cases remaining undiagnosed. The disease is no longer confined to affluent or urban populations; it is increasingly affecting younger adults and rural communities. Delayed or inaccurate diagnosis can lead to long-term damage to the heart, kidneys, eyes, and nerves.

Recommended Approach to Monitoring

The authors propose a resource-adapted framework for India:

• In low-resource settings: Use the oral glucose tolerance test (OGTT) for diagnosis and self-monitoring of blood glucose (SMBG) two to three times per week, combined with basic hematologic screening.

• In tertiary care settings: Combine standardized HbA1c testing with OGTT for diagnosis, and use continuous glucose monitoring (CGM) along with alternative markers such as fructosamine for monitoring.

• Where necessary, conduct iron studies, hemoglobin electrophoresis, and quantitative G6PD testing.

The review concludes that while HbA1c remains a valuable tool, it should not be used in isolation in India’s diverse population. A combined, context-specific approach to diagnosis and monitoring may help prevent delayed treatment and reduce diabetes-related complications.

REFERENCE: Samajdar, Shambo Samrat et al.; The limitations and fallacies of relying on glycosylated hemoglobin for diagnosing and monitoring diabetes in Indian populations; The Lancet Regional Health - Southeast Asia, Volume 0, Issue 0, 100724; https://doi.org/10.1016/j.lansea.2026.100724