What is HbA1C?
HbA1c is also known as glycosylated hemoglobin. Hemoglobin is a component of red blood cells that carries oxygen. When hemoglobin binds with glucose in the blood, HbA1c is formed. The higher the glucose concentration in blood, the higher the levels of HbA1c.
Red blood cells can survive for 8 to 12 weeks in our body. That's why the levels of HbA1c are not influenced by daily fluctuations in the blood glucose concentration, but reflect the average glucose levels over the last 6 to 8 weeks. Because HbA1c can be used to tell how well the blood glucose level has been controlled in the past, it's an important tool to track the progress of any diabetes management plan.
How to interpret the values?
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| a diabetes control card |
- In non diabetic patients the normal HbA1c level is less than 7%. HbA1c levels over 6% is sufficient to identify people who are at an increased risk for diabetes.
- In people with diabetes, a HbA1c levels below 6.5% shows good diabetes control.
- For people who are at risk for getting hypoglycemia, a level of 7.5% is an acceptable target.
How often should you repeat measurement?
If your diabetes is in good control, repeat HbA1c measurement every 6 month. If you are trying to improve control or if you are making changes in your treatment plan, repeat the test after 3 months. Repeating HbA1c test sooner than 6 weeks after the last measurement provides little or no information and is not cost effective.
What are the limitations of HbA1c?
Although HbA1c test is an important tool that tells how well you're doing over the past months, it can't replace daily blood glucose monitoring for those who need it. HbA1c levels can't be used to adjust insulin dosage, nor can it detects the presence of hyperglycemia or hypoglycemia.
In people with kidney disease, chronic excessive alcohol intake, and hypertriglyceridemia, HbA1c levels may be falsely increased. Blood loss either acute or chronic and several diseases of the red blood cells like thalassemia and sickle cell disease may falsely decreased HbA1c levels.
