The HbA1c blood test (also known as the glycated hemoglobin, glycosylated hemoglobin, or A1c test) is a crucial blood test used to measure your average blood sugar (glucose) levels over the past two to three months.
It's one of the primary tools used to diagnose and monitor diabetes and prediabetes.
What the Test Measures
The test measures the percentage of your hemoglobin—a protein inside red blood cells that carries oxygen—that is coated with glucose.
* When glucose enters the bloodstream, it binds to hemoglobin. This is called glycation.
* Since red blood cells live for about 90 to 120 days (3 to 4 months), the HbA1c result reflects the average glucose level attached to the hemoglobin over that lifespan, providing a long-term snapshot of your blood sugar control.
This differs from a standard finger-prick blood glucose test, which only shows your blood sugar level at a single moment in time.
Purpose of the HbA1c Test
The test serves two main purposes:
* Diagnosis: It is used to screen for and diagnose prediabetes and Type 2 diabetes.
* Monitoring: For individuals already diagnosed with diabetes (Type 1 or Type 2), it is used to monitor how well their blood sugar levels are being managed over time, helping to evaluate the effectiveness of their treatment plan (diet, exercise, and medication).
Interpreting HbA1c Results
HbA1c results are reported as a percentage. The higher the percentage, the higher your average blood sugar levels have been.
| HbA1c Result | Status | Indication |
|---|---|---|
| Below 5.7% | Normal | You do not have diabetes. |
| 5.7% to 6.4% | Prediabetes | You have an increased risk of developing diabetes. |
| 6.5% or higher | Diabetes | You have diabetes. |
For people with diabetes, the target HbA1c level is often below 7.0%, but this goal may be higher or lower depending on individual health factors, age, and other conditions, and is determined by a healthcare provider.
Test Preparation
One major advantage of the HbA1c test is that it does not require fasting. You can eat and drink normally before the test as it measures a long-term average, not an immediate blood glucose level.
However, if your doctor orders other blood tests at the same time (such as a fasting glucose or lipid panel), you may need to follow fasting instructions for those specific tests. Always confirm preparation details with your healthcare provider.