The HbA1c test, also known as the Hemoglobin A1c, Glycated Hemoglobin, or A1c test, measures the average blood sugar (glucose) levels over the past 2 to 3 months. It works by identifying the percentage of hemoglobin (the protein in red blood cells that carries oxygen) that is coated with sugar. The higher the HbA1c level, the higher the risk of developing complications related to diabetes, such as nerve damage or cardiovascular disease. This test is crucial for diagnosing prediabetes and diabetes, as well as for monitoring how well diabetes is being managed over time. Essentially, it provides a longer-term gauge of blood sugar control than daily blood glucose tests.