Daijiworld Media Network – New Delhi
New Delhi, Feb 11: The widely used HbA1c blood test for diagnosing and monitoring diabetes may give misleading results in millions of people across South Asia, especially in India, due to the high prevalence of anaemia and inherited blood disorders, a new analysis published in Lancet Regional Health – Southeast Asia has warned.
The review, led by senior endocrinologist Prof Anoop Misra, points out that HbA1c levels — which indicate average blood glucose by measuring haemoglobin glycation — can either under- or overestimate actual blood sugar levels in individuals with conditions affecting red blood cells. These include iron deficiency anaemia, haemoglobinopathies and glucose-6-phosphate dehydrogenase (G6PD) deficiency.
“In regions like India, where nutritional anaemia and red blood cell disorders are widespread, exclusive reliance on HbA1c can result in misclassification of diabetes status,” said Prof Misra, Chairman of Fortis C-DOC Center of Excellence for Diabetes.
The authors noted that in some parts of India, more than half the population suffers from iron deficiency anaemia, which can significantly distort HbA1c readings and complicate both diabetes diagnosis and long-term monitoring. The review also cautioned that undetected G6PD deficiency in men could delay diabetes diagnosis by up to four years, potentially increasing the risk of serious complications.
Endocrinologist Dr Shashank R Joshi of Mumbai’s Joshi Clinic said HbA1c variability is observed even in well-equipped urban hospitals due to red blood cell abnormalities. “In rural and tribal areas, where anaemia and inherited blood disorders are more common, discrepancies may be even greater,” he added.
The study further highlighted that inconsistent laboratory quality control across regions can worsen inaccuracies, making interpretation of HbA1c results more challenging. As a result, public health surveys that rely solely on HbA1c may underestimate or misrepresent India’s true diabetes burden.
To address these concerns, the review recommends a resource-adapted approach to diabetes diagnosis and monitoring. In low-resource settings, it suggests using oral glucose tolerance tests (OGTT) along with periodic self-monitoring of blood glucose and basic haematological screening. In tertiary care centres, a combination of HbA1c, OGTT, continuous glucose monitoring and alternative biomarkers such as fructosamine is advised.
Dr Shambho Samrat Samajdar, a co-author from Kolkata, said integrating glucose-based tests with haematological assessments offers a more accurate picture of diabetes risk and can help improve public health estimates and resource allocation.