The hemoglobin A1c test, also called HbA1c, glycated hemoglobin test, or glycohemoglobin, is an important blood test that shows how well your diabetes is being controlled. Hemoglobin A1c provides an average of your blood sugar control over the past 2 to 3 months and is used along with home blood sugar monitoring to make adjustments in your diabetes medicines.
Hemoglobin is found in red blood cells, which carry oxygen throughout your body. When your diabetes is not controlled (meaning that your blood sugar is too high), sugar builds up in your blood and combines with your hemoglobin, becoming "glycated." The average amount of sugar in your blood can be found by measuring your hemoglobin A1c level. If your glucose levels have been high over recent weeks, your hemoglobin A1c test will be higher.
Sometimes, living with diabetes can seem like a full-time job -- trying to keep up with everything you need to do for proper diabetes care.
"Diabetes is a very time-consuming disease to manage well," says Karmeen Kulkarni, MS, RD, CDE, and former president of health care and education for the American Diabetes Association. "The medication, the food, the physical activity -- you add life in general to that whole picture and it ends up being quite challenging."
For people without diabetes, the normal range for the hemoglobin A1c test is between 4% and 5.6%. Hemoglobin A1c levels between 5.7% and 6.4% indicate increased risk of diabetes, and levels of 6.5% or higher indicate diabetes. Because studies have repeatedly shown that out-of-control diabetes results in complications from the disease, the goal for people with diabetes is a hemoglobin A1c less than 7%. The higher the hemoglobin A1c, the higher the risks of developing complications related to diabetes.
People with diabetes should have this test every 3 months to determine whether their blood sugars have reached the target level of control. Those who have their diabetes under good control may be able to wait longer between the blood tests, but experts recommend checking at least 2 times a year.
People with diseases affecting hemoglobin, such as anemia, may get abnormal results with this test. Other abnormalities that can affect the results of the hemoglobin A1c include supplements such as vitamins C and E and high cholesterol levels. Kidney disease and liver disease may also affect the result of the hemoglobin A1c test.