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What is an A1C (Glycated Hemoglobin)?

A1C is a blood test that measures the average level of blood glucose over the last 2-3 months. Glucose sticks to the hemoglobin (Hb) in red blood cells and causes some of it to change (or glycate) and form A1C.

If blood glucose levels are always between 4-8 mmol/L before and after meals, 7 days per week, then the amount of A1C that forms will be between 4 and 6 per cent (the usual laboratory range).