Haemoglobin (Hb) consists of four protein subunits, each containing a heme moiety, and is the red-pigmented protein located in the erythrocytes. HbA1c is one of the glycated haemoglobins. In the erythrocytes, the relative amount of HbA converted to stable HbA1c increases with the average concentration of glucose in the blood.
The conversion to stable HbA1c is limited by the erythrocyte’s life span of approximately 100 to 120 days. As a result, HbA1c reflects the average blood glucose level during the preceding 2 to 3 months.
HbA1c is thus suitable to monitor long-term blood glucose control in individuals with diabetes mellitus.
