This test determines a person’s average glucose levels over the past 3 months/ 12 weeks. However, it does not reflect daily fluctuations. It calculates the percentage of blood sugar linked to hemoglobin. If your blood sugar levels are high, it means that more amount of hemoglobin(red cells) is attached with sugar. This test is assumed to be more convenient for the patients than the other tests since it does not require fasting and can be done at any time of the day. It is recommended that each patient should do this diagnostic test at least twice a year.
For an individual diabetic patient, the recommended value of HbA1C ≤7%, if a person has a value of HbA1C ≥ 6.5%, he is considered to be diagnosed with diabetes.
These tests are usually reliable, however there are limitation for patient with anemia, pregnant women or having uncommon form of Hemoglobin.