Common Diabetes Test May Be Inaccurate for Millions in India, says Lancet study

Researchers publishing in The Lancet Regional Health: Southeast Asia have cautioned that the HbA1c test, widely used to diagnose and monitor diabetes, may not accurately reflect blood sugar levels in large sections of the Indian population.

The test measures average glucose levels over two to three months by assessing glucose-coated haemoglobin. However, conditions that affect haemoglobin, such as anaemia, haemoglobinopathies, and G6PD deficiency, can distort readings and lead to under- or overestimation of blood sugar.

Given India’s high burden of iron deficiency anaemia and inherited blood disorders, experts warn that HbA1c values may not reliably represent true metabolic status in many patients.

Experts Warn of Delayed Diagnosis and Misclassification

The review, led by Professor Anoop Misra, highlights that exclusive reliance on HbA1c can result in misclassification of diabetes status. Some patients may receive a delayed diagnosis, while others could be wrongly labelled as diabetic.

Co-author Shashank Joshi noted that even advanced urban hospitals face challenges due to red blood cell variations, while rural and tribal regions may experience greater inaccuracies. In men with undetected G6PD deficiency, diagnosis could be delayed by up to four years, increasing the risk of complications.

Inconsistent laboratory quality control further complicates interpretation, raising concerns about public health surveys that depend solely on HbA1c data to estimate India’s diabetes burden.

Call for Combined Testing and Resource-Based Approach

The authors recommend a more comprehensive and resource-sensitive approach to diabetes diagnosis and monitoring. In low-resource settings, they suggest using oral glucose tolerance tests, regular self-monitoring of blood glucose, and basic blood tests.

In tertiary care centres, HbA1c should be combined with glucose tolerance testing, continuous glucose monitoring, and alternative markers such as fructosamine. Where required, advanced investigations like iron studies and G6PD testing should be included.

The framework stresses that testing strategies must be tailored to local healthcare capacity and patient risk factors, especially in regions where anaemia and blood disorders are widespread.

(With inputs from ANI)