Glycated Haemoglobin HbA1c

In the 1960s, scientist noticed that in people with diabetes a minor component of human hemoglobin A was elevated. This component is called Hemoglobin A1c. Over the last 2 decades it is commonly used measure of average glycaemia over the preceeding months.

It is a formed a result of a stable and irreversible bind between glucose and a free amino group of the valine residues in the N-terminal of beta-chain of hemoglobin Ao (N-[1-deoxyfructosyl]hemoglobin). The resulting Schiff base is unstable and undergoes an irreversible Amadori rearrangement to form a stable ketoamine.

A direct relationship exists between HbA1c and average blood sugar levels because the red blood cells are continuously glycated during their 120-day lifespan and the rate of glycohemoglobin formation is proportional to the ambient glucose concentration.

haemoglobin diagram