Hemoglobin A1c or HbA1c is a part of hemoglobin to which glucose is bound in blood. HbA1c levels depend on the overall blood glucose concentration in the body. The higher the glucose levels, the higher HbA1c readings. Levels of HbA1c are not influenced by daily fluctuations in the blood glucose concentration. They reflect the average glucose levels over the prior 3 month period. Therefore, HbA1c is a useful indicator of how well the blood glucose level has been controlled in the recent past. It is be used to monitor the effects of diet, exercise, and drug therapy on blood glucose in diabetic patients. Since HbA1c is not influenced by daily fluctuations in blood glucose concentration, it cannot be used to monitor day to day blood glucose concentrations. HbA1c values are being increasingly used to diagnose diabetes since 2013. It is becoming a popular method of diagnosis of diabetes since no fasting is required nor is the inconvenience of ingesting glucose. The interpretation of values are as follows :
- Normal: Less than 5.7%.
- Pre diabetes: Between 5.7% and 6.4%.
- Diabetes: 6.5% or higher