The A1C test is a vital clinical diagnostic tool that measures the average blood sugar levels of an individual over the preceding two to three months. It works by determining the percentage of hemoglobin—the oxygen-carrying protein in red blood cells—that has glucose attached to it. Because red blood cells have a lifespan of approximately 120 days, the A1C provides a stable, long-term overview of glycemic control, unlike a standard glucose test which only provides a snapshot of a single moment.
In metabolic health management, A1C is the gold standard for diagnosing prediabetes and type 2 diabetes, as well as for monitoring the effectiveness of weight loss and dietary interventions. A reading below 5.7% is considered normal, while levels between 5.7% and 6.4% indicate prediabetes. Lowering A1C is a primary objective in metabolic reset protocols, as it reflects improved insulin sensitivity and a reduced risk for the long-term complications associated with chronic hyperglycemia.
The definitive guide by Russell Clark, FNP-C, APRN