The Hemoglobin A1c test, often called HbA1c, is a blood test used to check how well a person is managing their blood sugar over time. The American Diabetes Association (ADA) suggests that people who have their blood sugar levels under control should get this test done twice a year. However, if someone’s blood sugar levels are often too high or not stable, they should get the test done four times a year, which means once every three months. The results of the test are measured against standards set by the ADA, which help doctors understand whether a person’s blood sugar levels are in a good range, too high, or too low.