Normal range: 4 – 5.6 % (lower is better)
HbA1c reflects your average blood glucose over the past 2-3 months. It works by measuring the percentage of hemoglobin (the protein in red blood cells) that has glucose stuck to it. The higher your blood sugar has been running, the more glucose-coated hemoglobin you will have. It is the standard test for diagnosing and monitoring diabetes. Below 5.7% is normal, 5.7-6.4% is prediabetes, and 6.5% or above is diabetes. Unlike fasting glucose, HbA1c does not require fasting.
A normal HbA1c is 4 – 5.6 %. Lower is better.
Elevated HbA1c reflects chronically high blood sugar, most commonly from insulin resistance, prediabetes, or type 2 diabetes. A diet high in refined carbohydrates and sugar, combined with physical inactivity and excess weight, is the most frequent pattern.
Conditions that affect red blood cell lifespan can alter HbA1c independently of glucose: iron deficiency anemia falsely raises it, while hemolytic anemia falsely lowers it. Chronic kidney disease and heavy alcohol use can also distort results. Certain hemoglobin variants (common in people of African, Southeast Asian, or Mediterranean descent) may affect accuracy.
The same lifestyle changes that improve fasting glucose improve HbA1c: regular exercise, weight loss, reducing refined carbs and sugar, eating more fiber, and managing stress. Because HbA1c reflects a 2-3 month average, it takes time to see changes. Medications including metformin, GLP-1 receptor agonists (like semaglutide), SGLT2 inhibitors, and insulin all lower HbA1c. Even a 0.5% reduction in HbA1c significantly reduces the risk of diabetes complications.
HbA1c is most highly correlated with Albumin and Total Bilirubin. Here are the top biomarkers correlated with HbA1c, based on 500,000 tests done by Empirical Health.
The percentage shows how strongly two biomarkers move together. A higher number means the relationship is stronger. Green = rises and falls together. Orange = one rises as the other falls.
You can test your HbA1c for $190 as part of Empirical's comprehensive health panel, which includes 100 biomarkers.
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