An HbA1c test (Hemoglobin A1c) is a blood test used to measure the average blood sugar levels over the past two to three months. It helps in diagnosing and monitoring diabetes and prediabetes by showing how effectively blood glucose is being controlled over time. The test measures the percentage of hemoglobin, a protein in red blood cells, that is coated with sugar (glycated). An HbA1c level below 5.7% is considered normal, 5.7% to 6.4% indicates prediabetes, and 6.5% or higher suggests diabetes. Doctors commonly recommend this test for people with symptoms of diabetes, a family history of the disease, obesity, or those already undergoing diabetes treatment. Regular HbA1c testing helps prevent complications and supports better long-term diabetes management.