The widely used glycated haemoglobin (HbA1c) test may not accurately reflect blood glucose levels for millions of Indians, according to a new evidence-based viewpoint published in The Lancet Regional Health – Southeast Asia on February 9, 2026.
HbA1c measures average blood sugar over the previous two to three months by estimating the percentage of haemoglobin coated with glucose. Typically, values below 5.7% are considered normal, 5.7–6.4% indicate prediabetes, and 6.5% or higher suggest diabetes. However, researchers caution that this test may produce misleading results in populations with a high prevalence of anaemia, haemoglobin disorders, and red blood cell enzyme deficiencies—conditions common in India.
Why HbA1c Results Can Be Misleading
As reported by NDTV, led by Professor Anoop Misra, Chairman of Fortis C-DOC Centre of Excellence for Diabetes, the review questions reliance on HbA1c as a standalone diagnostic or monitoring tool in South Asia. Since HbA1c reflects haemoglobin glycation, any condition that alters haemoglobin quantity, structure, or lifespan—such as iron deficiency anaemia, haemoglobinopathies, or G6PD deficiency—can distort results.
As a result, HbA1c may either overestimate or underestimate actual blood glucose levels, leading to delayed diagnosis, misdiagnosis, or inappropriate treatment decisions.
India’s Unique Risk Profile
In several regions of India, more than 50% of the population suffers from nutritional anaemia. Such widespread iron deficiency can significantly skew HbA1c readings, affecting both diagnosis and long-term monitoring of diabetes. The review notes that reliance on HbA1c alone could delay diabetes diagnosis by up to four years in men with undetected G6PD deficiency, increasing the risk of complications.
In addition, inconsistent laboratory quality control further complicates interpretation, while public health surveys based solely on HbA1c may underestimate or misrepresent India’s diabetes burden.
A Resource-Adapted Diagnostic Framework
To address these challenges, the authors propose a tiered, resource-sensitive framework. In low-resource settings, they recommend oral glucose tolerance testing (OGTT) for diagnosis and self-monitoring of blood glucose two to three times weekly, combined with basic blood tests.
In tertiary care centres, they advise combining standardised HbA1c testing with OGTT, continuous glucose monitoring, and alternative markers such as fructosamine. Where indicated, iron studies, haemoglobin electrophoresis, and quantitative G6PD testing should support clinical decisions.
Call for a Combined Testing Approach
Overall, the review emphasises that in anaemia-endemic regions like India, HbA1c should not function as a solitary gold standard. Instead, clinicians should combine it with complementary tests to ensure accurate diagnosis, effective monitoring, and better diabetes outcomes.