Glycated Hemoglobin (HbA1c) Test
The HbA1c test is a procedure used to diagnose or monitor both type 1 and type 2 diabetes. The test requires only a sample of peripheral blood.
General Description
The glycated hemoglobin (HbA1c) test, also known as the glycosylated hemoglobin test, is a blood test that measures the amount of glucose present in the blood. It is a common diagnostic method for both type 1 and type 2 diabetes.
This test provides an overview of blood glucose levels over the past two to three months, which corresponds to the estimated lifespan of red blood cells. Therefore, it is an appropriate method for monitoring patients who have already been diagnosed. This type of measurement is performed as a medical control; it is not the same as the daily tests patients perform themselves.
The HbA1c test measures the percentage of hemoglobin—a protein that carries oxygen through the blood—that is coated with sugar. The higher this percentage, the greater the risk of complications.
When is it indicated?
The glycated hemoglobin test is indicated both for individuals suspected of having diabetes, to confirm or rule out the diagnosis, and for those who have already been diagnosed with the disease. The frequency of testing varies depending on the circumstances:
- Every three years: Individuals over 45 years old.
- Annually: Individuals with prediabetes, as they are at high risk of developing diabetes if lifestyle changes are not made.
- Twice a year: Patients with type 2 diabetes who do not require insulin and maintain their blood sugar levels within the target range established by their specialist.
- Four times a year: Patients with type 1 diabetes or those with type 2 diabetes who have difficulty controlling their glucose levels.
How is it performed?
It is recommended to wear a short-sleeved shirt or easily removable clothing, as the arm must be exposed for the blood draw.
A slight pinch is normal when the needle is inserted into the vein, but it lasts only a moment. To reduce the risk of bruising, it is advisable to apply pressure to the area for a few minutes. Mild dizziness may also occur after the blood draw, which usually resolves by lying down for a few minutes with the legs elevated.
Results are typically available within one or two days. Each patient’s situation is unique, so results should be evaluated by a specialist. In general:
- Normal value: Less than 5.7%.
- Prediabetes (risk of developing type 2 diabetes): Between 5.7% and 6.4%.
- Diabetes: Greater than 6.5%.
Medical specialties that request a glycated hemoglobin test
The HbA1c test is commonly requested in primary care, cardiology, endocrinology, hematology, and genetics.
How to prepare
No special preparation is required for an HbA1c test.
