Hemoglobin A1c TestThe HbA1c test measures your average blood sugar levels over the past 3 months, helping to assess your risk for prediabetes or diabetes. If you already have diabetes, it shows how well you're managing your blood sugar. Higher HbA1c levels indicate prolonged high blood sugar. Signs & Symptoms of Diabetes Diabetes symptoms can be subtle. Consider testing if you're experiencing: Frequent urination Excessive thirst or hunger Fatigue or blurred vision Dry