HbA1c is a blood test used to measure long-term blood sugar levels. It is usually done after a person has fasted for 8 to 12 hours. It is used to help diagnose and monitor diabetes.
What is HbA1c?
HbA1c (or glycated hemoglobin) is a measure of the average amount of glucose in your blood over the past 2-3 months. It is a type of hemoglobin, a protein in red blood cells that carries oxygen throughout the body. When glucose levels are high, some of the hemoglobin molecules become glycated, meaning they are bonded with glucose molecules. The more glucose in the blood, the higher the HbA1c.
Why is HbA1c Done Fasting?
Fasting is necessary for getting an accurate reading of your HbA1c level. When you eat, your body produces glucose. This glucose is then stored in your cells and eventually released into your bloodstream. If you have recently eaten, your HbA1c will be higher than it would be if you had been fasting. Therefore, in order to get an accurate reading, it is necessary to fast for 8-12 hours before the test.
What Do HbA1c Results Mean?
HbA1c results are expressed as a percentage. Generally, the higher the percentage, the higher your blood glucose levels have been over the past 2-3 months. Normal HbA1c levels are less than 5.7%, prediabetes is 5.7-6.4%, and diabetes is 6.5% or higher.