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.