Can HbA1c help with blood sugar?

HbA1c (glycated hemoglobin) is a well-established biomarker reflecting average blood glucose over the past 2–3 months. It is widely used for diagnosing and monitoring type 2 diabetes and prediabetes. The evidence is strong: numerous clinical trials and guidelines (e.g., from the American Diabetes Association) support its utility. However, HbA1c has limitations: it can be affected by anemia, kidney disease, hemoglobin variants, or pregnancy. It also does not capture short-term glucose fluctuations or hypoglycemia. For daily therapy adjustments, continuous glucose monitoring (CGM) or fasting glucose may be more appropriate. A normal HbA1c is below 5.7%, prediabetes 5.7–6.4%, and diabetes ≥6.5%. The test is helpful but not definitive on its own – it should be interpreted alongside lifestyle, medication, and individual health factors.