‘My blood glucose is always high (160-220) but my HbA1c is always under 6. Why?’

Quora users have been asking: why can someone have constantly high blood glucose levels (160-220 mg/dL) while still having an HbA1c under 6%? Endocrinologist Dr Pranav Ghody explained that the two results shouldn't be assumed to be incorrect or reassuring based solely on this discrepancy. HbA1c measures average glucose levels from the previous two to three months, whereas individual glucose readings are a single moment in time.

However, a consistent glucose range of 160-220 mg/dL warrants further investigation. Dr Ghody stressed that the HbA1c can sometimes appear lower than actual average glucose due to factors such as red blood cell lifespan or destruction rates, haemoglobin variants, or certain conditions. In India, haemoglobin variants like HbE and other haemoglobinopathies should be considered, as they can interfere with HbA1c testing.

The lab methodology used for HbA1c is also crucial, as testing methods can impact results. If glucose readings and HbA1c don't align, patients should have their blood glucose verified with a reliable glucometer or continuous glucose monitor. Doctors may repeat the HbA1c test using appropriate lab methods and examine blood counts and other relevant tests.

Dr Ghody emphasized that even with a low HbA1c, persistently high glucose levels should not be ignored, as they can still lead to complications.