A hemoglobin A1c test is a blood test designed to diagnose Type 1 and Type 2 diabetes and determine how well a person is managing his diabetes, according to Mayo Clinic. The test measures a person's average blood sugar level over two to three months; a higher A1c level indicates poor blood sugar management and greater risk for complications.
As of 2015, the American Diabetes Association, the European Association for the Study of Diabetes and the International Diabetes Federation all recommend the hemoglobin A1c test as the primary test to diagnose prediabetes and diabetes, says Mayo Clinic. Because the test determines blood sugar levels over two to three months rather than a single point in time, experts believe it is a better overall reflection of a patient's average blood sugar.
The normal level for hemoglobin A1c hemoglobin is between 4 and 5.6 percent, states WebMD. Levels between 5.7 and 6.4 percent indicate an increased risk of diabetes, and levels greater than 6.5 percent confirm diabetes. For confirmed diabetics, the ideal A1c range is less than 7 percent.
After the initial diagnosis, doctors use hemoglobin A1c to plan or adjust a patient's care plan, says Mayo Clinic. The frequency of the test depends on the type of diabetes the patient has, whether he uses insulin or other diabetes medications and how well he manages his blood sugar. Patients with higher A1c levels require more frequent testing to monitor changes in blood sugar.