India, March 15 -- HbA1c is the most widely used marker for diagnosing and monitoring diabetes. It reflects average blood glucose over the previous three months by measuring the percentage of haemoglobin that has been glycated, essentially, how much sugar has attached itself to your red blood cells over their lifespan. It's convenient, doesn't require fasting, and gives a longer-term picture than a single blood glucose reading. But there's a critical blind spot that most patients and frankly, many clinicians overlook. HbA1c assumes your red blood cells are behaving normally. When they aren't, the number on your report can be dangerously misleading.

What is the correlation between haemoglobin and HbA1c? HbA1c depends on haemoglobin being...