What is Hemoglobin A1c?
A1C measures your average blood sugar over the past 2-3 months. Below 5.7% is normal. Between 5.7-6.4% signals prediabetes. 6.5% or higher indicates diabetes. The 2026 AHA/ACC guidelines include A1C in the new PREVENT equations for predicting heart disease, because blood sugar control directly impacts cardiovascular risk.