The test does not require any fasting or other special preparations. Normal medications may be taken before the test.
Why It Is Used
The hemoglobin blood test is primarily used as a means of calculating average levels glucose in the blood over an extended period of time.
How It Works
This test is used to evaluate glucose levels in the blood over the 2 to 3 months previous to the test. This test is very important in managing one’s diabetes. Scientists believe that keeping the blood sugar in the body within normal range can help individuals with diabetes to avoid many of the risks and side effects that people with diabetes often face. The benefit of the hemoglobin A1c blood test is that is provides information on overall glycemic health over a several month period. Other blood tests of glucose level are highly sensitive to determining glucose levels at the time the test is taken, but they do not give information on average glucose blood levels.
The test works by measuring the hemoglobin A1c level. Hemoglobin is stored in the red blood cells. When glucose levels are high, the sugar starts to combine with the hemoglobin. It takes the body 8 to 12 weeks to bring hemoglobin A1c levels back to normal. Therefore, if hemoglobin A1c levels are high, that means that there has been a high level of glucose in the blood over the last 2 to 3 months.
Test results are interpreted by looking at the levels of hemoglobin A1c found in the blood. Hemoglobin A1c results are represented as a percentage of glucose in the blood. Glucose is measured in milligrams per deciliter (mg/dL). Normal results vary based on what test is being used. The following results are represent numbers based on the hemoglobin blood test A1c.
- Normal: < 5.7 %
- Pre-diabetes / Increased risk of diabetes 5.7 % – 6.4 %
- Diabetes: > 6.5 %
- A1c 6 % represents an approximate plasma glucose level of 126
- A1c 7 % represents an approximate plasma glucose level of 154
- A1c 8 % represents an approximate plasma glucose level of 183
- A1c 9 % represents an approximate plasma glucose level of 212
- A1c 10 % represents an approximate plasma glucose level of 240
- A1c 11 % represents an approximate plasma glucose level of 269
- A1c 12 % represents an approximate plasma glucose level of 298