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Getting ready for an A1C test: what it is, the numbers, what can change them, and your goal

For anyone sent for an A1C blood test (also called hemoglobin A1C or HbA1c), or holding a result they cannot read: for prediabetes, type 2 diabetes, or managing diabetes. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK, part of the NIH) says the A1C test gives information about your average blood glucose, also called blood sugar, over the past 3 months. This page passes on, by name, what NIDDK says: what the test measures, and that you don’t have to fast for it; the numbers NIDDK gives for prediabetes and diabetes, and why a second test confirms them; pregnancy and the other blood glucose tests; why results can differ, and what can make an A1C wrong, from anemia and sickle cell to hemoglobin variants; and goals after a diagnosis. It builds the words to say and the questions to ask, and prints a card for the fridge with a line for your number.

Your heart, blood pressure, blood sugar, thyroid or blood, and not sure this is the right page? The pages on this site for a heart attack or stroke, blood pressure, AFib, heart failure, cholesterol, diabetes and prediabetes, the thyroid, anemia, sickle cell and menopause, on one list.

Another test coming up, or not sure this is the right page? The guides on this site for a colonoscopy, an endoscopy, a GI series, ERCP, a biopsy, a cystoscopy, urodynamic tests, urinary tract imaging, prostate tests, an A1C and thyroid tests, on one list.

This page and its wording were written with AI (Claude) for Scarlet Beast (our AI policy). No doctor or nurse has reviewed it. The facts were read on October 18, 2026 on NIDDK’s The A1C Test & Diabetes page (NIH), last reviewed in April 2018, and its Spanish version, last reviewed in April 2019; they say the same things. The cards also point to NIDDK’s Diabetes Tests & Diagnosis, Risk Factors for Type 2 Diabetes and The A1C Test & Race/Ethnicity pages. The numbers (the past 3 months; below 5.7, 5.7 to 6.4, and 6.5 percent or above; fasting at least 8 hours for the other tests; 24 to 28 weeks; no later than 12 weeks after the baby is born, then every 3 years; 6.8 reported from 6.4 to 7.2; at least twice a year; below 7, and 7 to 8 percent; the past 30 days) are NIDDK’s. Ours: 911 for trouble breathing, chest pain, or fainting, or someone with diabetes who passes out or cannot swallow; pointing to our diabetes page for low blood sugar; never stopping or changing a prescribed medicine on your own; asking which test it is and whether to fast; writing your number and the date on the card; asking whether the blood went to a lab and when the second test is; telling them about anemia, sickle cell, kidney or liver disease, blood loss, a transfusion or dialysis, and your family’s descent; asking what your own goal is; the card; 988 when it is too much; health centers when money is tight; and the order of the steps. What we left out: brands and doses, the eAG conversion table, the clinical trials section, and the references. This page saves nothing and loads no trackers.