Does fasting affect A1C?

Fasting does not significantly affect A1C test results. The A1C test measures your average blood sugar levels over the past 2-3 months by assessing the percentage of hemoglobin that is glycated (coated with sugar). Since it reflects long-term glucose levels, short-term changes like fasting do not impact the results.

However, fasting may be required for other tests (e.g., fasting blood glucose or cholesterol tests) that are sometimes done alongside the A1C test. Always follow your healthcare provider's instructions before testing.