If you have diabetes, prediabetes, or a family history of diabetes, you may have heard your doctor mention the HbA1c test. But what does HbA1c actually tell you? In simple terms, the HbA1c test shows your average blood glucose level over roughly the past 2 to 3 months. Unlike a fasting blood sugar test, you usually don't need to fast for an HbA1c test. Doctors use it to help diagnose prediabetes...