This is a long term blood sugar monitoring test done to know the glycohemoglobin levels in the blood of persons who already have diabetes. Hemoglobin is the oxygen-carrying part of the red blood cells. Occasionally the hemoglobin of the red blood cells gets coated with glucose and it is called glycohemoglobin /glycosylated hemoglobin or HbA1c.

The normal range for HbA1c is usually about 4% to 6% in people without diabetes. HbA1c level will be high in a person with diabetes say up to 7%. If the level of HbA1c is more than 7%, adjustments should be made in the treatment plan and care should be taken to reduce the sugar levels. If it is 7% or less, the person with diabetes has achieved good glucose control.

How and when the test is done
The test is done by taking a blood sample from a vein in the forearm or from the hand. It can be done once in 3 months as red blood cells live about 3 months before it is recycled. The result will show the average level of glycohemoglobin for the past 3 months. Certain conditions like blood loss or transfusion, kidney disease, pregnancy, anemia etc can cause inaccurate test results.

The results are an indication of person's risk of developing long term complications from diabetes such as kidney failure, vision problems and leg or foot numbness.