Should a patient be fasting to have an A1c drawn?

The testing for Hemoglobin A1c (HbA1c) does not require fasting because it measures the average blood glucose levels over the previous two to three months. This test reflects the overall glycemic control and is affected by the amount of glucose to which the hemoglobin has been exposed over that time period, rather than the immediate levels of glucose in the bloodstream.

As a result, fasting does not influence the HbA1c results, making it unnecessary for patients to fast prior to this test. The accuracy of the A1c measurement is not contingent upon a fasting state, allowing for greater flexibility in testing times. This characteristic distinguishes A1c testing from other glucose tests, such as fasting glucose tests, which do require the patient to be fasting to provide meaningful results.