How often should A1c be checked?

With diabetes

The ADA recommends assessing glycemic status at least two times a year, and more often, such as every 3 months, for people who are not meeting their goals, have had a recent treatment change, have frequent or severe low or high blood sugar, or have a change in health (ADA Standards 2026, sec. 6). Adults whose glucose is stable within their goal range may only need an A1c twice a year (ADA Standards 2026, sec. 6). Glycemic status can be assessed with A1c, with CGM measures such as time in range, or both (ADA Standards 2026, sec. 6).

Point-of-care A1c tests in the clinic give a result during the visit, which helps with decisions, though they may be less accurate than lab tests (ADA Standards 2026, sec. 6). More on goals in A1c goals in diabetes.

With prediabetes

People with prediabetes (A1c 5.7% to 6.4%, or impaired fasting glucose or glucose tolerance) should be tested every year (ADA Standards 2026, sec. 2). See the prediabetes A1c range.

Without diabetes

For most people, screening begins at age 35; adults of any age with overweight or obesity and one or more risk factors are tested earlier (ADA Standards 2026, sec. 2). When results are normal, the ADA says repeat screening at least every 3 years is reasonable, sooner with symptoms or a change in risk such as weight gain (ADA Standards 2026, sec. 2). After gestational diabetes, screening continues every 1 to 3 years for life (ADA Standards 2026, sec. 2).

Children, teens and pregnancy

• Children and teens with type 2 diabetes: glycemic status at least every 3 months (ADA Standards 2026, sec. 14).
• Children and teens during periods of rapid growth: more often, such as every 3 months (ADA Standards 2026, sec. 6).
• Pregnancy with diabetes: because red blood cells change, A1c may need checking more often than usual, for example monthly (ADA Standards 2026, sec. 15). See A1c in pregnancy.

Why about 3 months?

A1c reflects average glucose over about the past 2 to 3 months, weighted toward the most recent weeks (ADA Standards 2026, sec. 6) (NIDDK). A repeat after only a few weeks shows part of a change, not all of it. For the timeline, see how fast A1c can change.

Frequently asked questions

How often should A1c be checked if you have diabetes?

The ADA says at least twice a year, and more often, for example every 3 months, for people not meeting their goals, after a treatment change, or with frequent low or high blood sugar.

How often should A1c be checked for prediabetes?

Every year, according to the ADA screening criteria.

How often should A1c be checked without diabetes?

Screening starts at age 35 for most people, earlier with risk factors. If results are normal, the ADA says repeating at least every 3 years is reasonable, sooner with symptoms or a change in risk.

Is it worth repeating an A1c after a few weeks?

A1c reflects about the past 2 to 3 months, so a repeat after a few weeks shows only part of a change. That is why measuring about every 3 months is the usual rhythm when things are changing.