The standard diabetes test, glycated haemoglobin (HbA1c), often used to diagnose and monitor type-2 diabetes, may give misleading results in South Asia, especially India. This is because many people have anaemia, haemoglobinopathies like sickle cell disease and thalassaemia, and glucose-6-phosphate dehydrogenase (G6PD) deficiency. A review published in Lancet Regional Health: Southeast Asia, led by Dr Anoop Misra from Fortis C-DOC Centre of Excellence for Diabetes, warns against relying on HbA1c alone for diabetes diagnosis or monitoring in India. The article highlights that poorly standardised HbA1c tests add to the confusion. Dr Misra said, “Overall, reliance solely on HbA1c is constrained by several clinical and biological factors in India. A multiparametric, risk-stratified approach that integrates oral glucose tolerance test, self-monitoring of blood glucose, and whenever possible, continuous glucose monitoring, in addition to relevant hematologic assessments are essential to enhance diagnostic and monitoring accuracy and inform appropriate treatment decisions, especially in primary care and resource-limited settings.” The article notes any condition affecting hemoglobin’s quantity, structure, or lifespan can distort HbA1c values, leading to wrong blood sugar estimates. Co-author Dr Shashank Joshi from Mumbai’s Joshi Clinic explained that iron-deficiency anaemia common in parts of India can change HbA1c results. “This would affect both diagnosis and monitoring thus misleading clinicians. Reliance on HbA1c alone could delay diagnosis by up to four years in men with undetected G6PD deficiency, potentially increasing risk of complications,” he warned. The report also mentions that type-1 diabetes patients may show a non-linear link between blood glucose and HbA1c. Diabetologist V. Mohan commented that while HbA1c is the gold standard to monitor diabetes control, it should not be the only test to diagnose diabetes. Rajeev Jayadevan, former president of Indian Medical Association, Cochin, added, “Studies from India have shown that correction of anaemia can reduce HbA1c level. Diagnosis of diabetes can’t be based on a single HbA1c value — the whole clinical picture must be considered.” The article was published on February 9, 2026 at 10:50 pm IST.