How Often Should You Get an A1C Test?

Written bySameer Patel — Founder & Editor

Last Updated Aug 5, 2026

How often should you get an A1C test?

Most people arrive at this question holding a piece of paper and a vague sense of being either overdue or tested too much. The honest answer depends on which of three situations you are in — so find yours below, then read the condition attached to it, because the condition is the part that changes the answer.

If you have been diagnosed with diabetes

The floor is two A1C tests a year, and the ceiling is set by your clinician rather than by a rule. Several things other than your last result can move you to a tighter interval, which Section 2 covers.

If your last result was in the prediabetes range

Two authoritative bodies publish two different retesting intervals for you, and you are better served seeing both than being handed an average. Section 6 gives each one with its source and its date.

If you are being screened and have never had a high result

There is no fixed number for you. Your schedule is built from your age and your risk factors — and if you are on Medicare, a separate coverage limit applies to screening, which Section 5 explains.

If you are reading this for someone else, a parent or a partner, the same three rows apply.

Sources: American Diabetes Association Standards of Care in Diabetes—2026, Sections 3 and 6; NIDDK, last reviewed April 2018; CDC A1C page, dated May 15, 2024. Every interval above is stated with the condition its source attaches to it.

If your real question is what the number means rather than when the next one is due, what your A1C result actually means is the better starting point. If the test turned up on routine blood work, a routine metabolic panel explains what those panels include, and whether you need to fast answers the question most people ask when booking.

ℹ️ Medical Disclaimer: This article explains published testing intervals and coverage rules for educational purposes. It does not diagnose any condition, recommend or adjust any medication or treatment, determine your personal testing schedule, or establish what your insurance plan will pay. Testing frequency, glycemic goals and treatment decisions belong to you and a board-certified physician — a primary care physician or an endocrinologist — who can see your full history. Coverage rules change and plans differ; confirm benefits with your own plan before assuming what is covered.

What actually decides how often you’re tested

Most people assume the number itself sets the schedule — that a higher A1C automatically means more frequent testing frequency checks. The current guideline does not work that way. It sets your interval from your status, and several parts of that status have nothing to do with your last result.

Your result is only one of the things that changes the answer

The 2026 Standards of Care name five circumstances that move a person from the twice-yearly floor to roughly quarterly assessment. Not meeting glycemic goals is one of them. The other four are a recent change in treatment, frequent or severe episodes of low or high blood sugar, a change in health status, and — for children and adolescents — periods of rapid growth and development.

Read that list again and notice what it is made of. Four of the five are events in your life rather than values on a lab report.

What counts as a change in treatment

A treatment change is not only a new prescription. Medicare’s own coverage rule, written for a different purpose entirely, describes more frequent assessment where a regimen “has been altered to improve control” or where an intercurrent event may have disturbed previously satisfactory control — and it names major surgery and glucocorticoid therapy as worked examples.

That is a useful way to think about it: a dose adjustment counts, and so does a hospital admission. A course of steroids for something unrelated to diabetes counts too, because of what steroids do to blood sugar while you take them.

Why a stable year can still mean more testing

This is the part that surprises people, and it is the reason the guideline lists conditions rather than thresholds. Your glycemic status is a description of your whole situation — your treatment, your stability, your recent health events — and not a synonym for your most recent percentage.

So a reader whose A1C has sat comfortably in range for twelve months may still move to quarterly checks after a medication change or a significant illness. That is not a sign anything has gone wrong — it is the schedule confirming that a change worked before another six months pass.

🩺 Physician Note: A common point of confusion is treating the testing interval as a reward or a penalty tied to the last number. Current guidance frames it as a categorical question instead — are you at your goal and stable, or has something changed? Your clinician sets that judgment with you, and it is worth asking directly which category you are in rather than inferring it from your result. If your treatment changed recently, ask your prescriber whether the next A1C should come sooner than the one already scheduled.

If you also monitor with a sensor rather than only with lab tests, the assessment picture is genuinely different — what continuous monitoring adds covers how the two are used together. And if your recent blood work carried a glucose value that seems to disagree with your A1C, how the two tests differ explains why that happens more often than most people expect.

Twice a year is a floor, not a schedule

If you are meeting your glucose goals and your treatment hasn’t changed, the American Diabetes Association’s Standards of Care in Diabetes—2026 set a minimum of two A1C tests a year — and about every three months if you are not. Both halves of that sentence are the recommendation. Neither half is the answer on its own.

What the 2026 guideline actually says

Recommendation 6.2 asks clinicians to assess glycemic status at least two times a year, and more frequently — for example every three months — for people not meeting their goals, with recent treatment changes, with frequent or severe low or high blood sugar, with changes in health status, or during periods of rapid growth in children and adolescents.

The federal patient page says the same thing in plainer words. The NIDDK page on the A1C test, last reviewed in April 2018, states that experts recommend people with diabetes have an A1C test at least twice a year, and that clinicians may check more often if you are not meeting your treatment goals.

That April 2018 date deserves a comment rather than a shrug. The reference behind that sentence is Section 6 of the 2018 edition of the same guideline, and eight annual editions later Section 6 still sets the same minimum — the page is old, but on this question the answer has not moved.

When the answer is closer to every three months

Roughly quarterly is not an upgrade or a warning. It is what the guideline asks for while something is being changed or watched, because a shorter interval is the only way to find out whether an adjustment worked.

The 2026 narrative puts it plainly: adults who have reached and are holding their goal range may only need testing twice a year, while people with less stable levels, intensive care plans, or unmet goals typically need it about every three months, with additional checks as needed.

Why the guideline stopped stating these separately

Here is the detail that matters most, and almost nobody reports it. In the 2024 edition, the twice-yearly floor and the quarterly interval were two separate recommendations. In the 2026 edition they are one.

Recommendation 6.2 now carries the floor, the tighter interval and all five triggering conditions inside a single sentence. You cannot quote one half of it without the other, because there is no longer a separate half to quote.

That change is worth knowing about because the most common error in this topic is quoting the floor alone — treating “at least twice a year” as though it read “twice a year.” The people who write the guideline appear to have noticed the same thing.

🩺 Physician Note: The full 2026 recommendation reads as one instruction with two settings. Assess glycemic status at least two times a year — and more frequently, about every three months, if you are not meeting your glycemic goals, if your treatment has recently changed, if you are having frequent or severe episodes of low or high blood sugar, if your health status has changed, or during periods of rapid growth and development in children and adolescents.

If any of those five describes you, the twice-yearly figure is not your interval. It is the minimum for someone whose situation is stable, and reading it as a schedule is the single most common way this guidance gets misapplied. Your clinician decides which setting applies to you, and that is a reasonable thing to ask about directly.

Part of the reason a retest interval exists at all is that a single measurement carries a margin of uncertainty around it — the honest margin around any single A1C explains how wide that margin is and why it is built into how the test is used.

✅ Patient Action: At your next visit, ask the clinician who manages your diabetes: “Which of these two schedules am I on right now — the twice-a-year one or the three-month one — and what would move me from one to the other?” Write the answer down with the date, so the next appointment starts from a known position.

Why three months, and not three weeks

If a testing interval feels arbitrary, it helps to know that the biology sets a floor on it. The glycated hemoglobin measurement cannot tell you anything new after two weeks, because it is not measuring what happened in those two weeks.

The test measures a window, not a day

The A1C reflects your average blood sugar over roughly three months. The CDC’s patient page on A1C testing explains the reason directly: red blood cells regenerate over about that period, and the test measures the proportion of them carrying sugar-coated hemoglobin.

That is why a single result cannot be read as a snapshot, and why retesting quickly after a change tends to disappoint: there has not been enough time for a new average to form.

🔬 How It Works: Sugar in your bloodstream attaches to hemoglobin, the protein inside red blood cells that carries oxygen. The more sugar there is and the longer it stays elevated, the more of it ends up attached. Because red blood cells live and are replaced over roughly three months, the proportion carrying attached sugar works as a running average of that period rather than a reading of today. Change something about your treatment and the average has to be rebuilt from the cells your body makes next — which is exactly as slow as it sounds.

Recent weeks count more than earlier ones

The window is not flat, and this is the nuance almost every explanation drops. The NIDDK page states that blood glucose levels in the past 30 days affect the A1C reading more than those in previous months.

So the “three-month average” is really a weighted average tilted toward the recent end. Institutions describe that window at different resolutions — the guideline calls it approximately two to three months, Medicare’s coverage rule describes the marker over a four-to-eight-week span, the CDC says three months. They are describing the same weighted window from different distances, not correcting one another.

What a repeat test can and cannot tell you

A repeat test can tell you whether an average moved. It cannot tell you what your blood sugar did last Tuesday — NIDDK is explicit that the A1C does not show sudden, temporary rises or falls.

That limit is the reason the interval exists rather than an inconvenience attached to it.

If you are trying to work out how much confidence to place in the result you already have, how precise a single A1C really is covers the measurement margin in detail. And if you have been checking daily and expected the A1C to move with what you were seeing, when your meter and your A1C disagree explains the several ordinary reasons they can differ.

What your insurance counts, and what it doesn’t

Here is where the same figure starts pointing in two directions. For a person managing diabetes, two tests a year is a minimum; for a person being screened under Medicare, two tests in twelve months is a maximum. Same number, opposite meaning, different reader — and merging them is the most common mistake made about coverage on this topic.

Screening and monitoring are covered under different rules

Screening means testing someone with no diagnosis to find out whether they have one. Monitoring means tracking a condition already diagnosed. Medicare covers both, under separate rules with separate limits.

For screening, the limit is a hard count. For monitoring there is no count at all — only a frequency expectation, and a documented route past it.

📊 Clinical Data Point: For diabetes screening, Medicare covers the A1C not more often than twice within the 12-month period following the most recent screening test, for all eligible beneficiaries — and the patient pays no coinsurance or deductible, because the U.S. Preventive Services Task Force’s August 2021 recommendation on diabetes screening includes the A1C at Grade B.

For monitoring an existing diagnosis, a different rule applies: testing more often than every three months is not considered reasonable and necessary for a patient whose diabetes is controlled — but the same rule states that testing for uncontrolled type 1 or type 2 diabetes may require more than four tests a year, and that medical necessity documentation must support testing beyond its own guidelines. — Source: CMS Transmittal 12694 (CR 13487), effective January 1, 2024; CMS National Coverage Determination 190.21.

The three-month expectation, and the exception written into it

“Medicare caps you at four A1C tests a year” is one of the most repeated claims in this subject, and the rule people cite to support it says otherwise — twice, in two different sections.

Medicare’s national coverage rule for A1C testing states that its own description section provides the clinical basis for testing more frequently than four times per year, and that medical necessity documentation must support such testing. Its reasons-for-denial section repeats the principle: where a policy identifies a frequency expectation, a claim exceeding it may be denied unless it is submitted with documentation justifying the increased frequency.

If you have been told you cannot have another test this year, that is the sentence worth knowing. There is a documented route, and it runs through your clinician’s order rather than through an appeal.

What changed on 1 January 2024

Before that date, the rule that added the A1C as a covered screening test shows Medicare covering it for diabetes management but not for diabetes screening; screening ran on fasting glucose and the glucose tolerance test. From 1 January 2024 the A1C became a covered screening test, with the twice-in-twelve-months limit above.

The direction of that change is usually reported backwards. Under the previous rule a beneficiary without a prediabetes diagnosis got one screening test every twelve months and a beneficiary with one got two; the new rule gives everyone two. For most people it roughly doubled the covered screening frequency rather than restricting it.

✅ Patient Action: If your clinician wants to test more often than the standard interval, ask them directly: “Can you document the medical necessity for the extra test on the order?” That documentation is what the coverage rule itself asks for. Separately, confirm with your own plan administrator what applies to you — Medicare’s rules are not automatically your plan’s rules.

The same floor-versus-coverage distinction shows up across routine testing. How often a cholesterol panel is repeated walks through the identical question for the lipid panel, and what Medicare covers for cholesterol testing sets out that panel’s coverage rules the same way this section does for the A1C.

If your result was in the prediabetes range

If your last A1C landed in the prediabetes range, you will find two different retesting intervals in two current, authoritative places. Both are right in the sense that both are what their authors published. Neither is a mistake, and you are better served seeing both than being handed an average.

Two current answers, and who gives each

The American Diabetes Association’s 2026 Standards of Care, Recommendation 3.1, asks that people with prediabetes be monitored for the development of diabetes at least annually, with the frequency modified by individual risk assessment. That recommendation was actively revised this edition — it was broadened to cover progression to all types of diabetes rather than type 2 alone.

The CDC’s A1C page, dated May 15, 2024, says that if your result shows prediabetes your doctor will likely recommend repeating the A1C every 1 to 2 years.

Why the looser interval is not an error

A public health agency writing for an entire population and a professional body writing for clinicians managing individuals are answering slightly different questions. Neither is wrong; they are calibrated for different jobs.

What they agree on is the part that resolves it for you. Both attach the same modifier — individual risk assessment — which means neither is actually recommending a fixed interval. The tighter figure is the safer default, and your own risk factors are what your clinician uses to choose.

There is a wider pattern here worth noticing. Even the task force whose recommendations drive preventive coverage describes the post-normal screening interval as uncertain, and its three-year figure as an approach that may be reasonable — yet that figure is almost always repeated flat, with the hedge removed. Intervals lose their qualifiers when they travel.

If you have never had a high result at all

The CDC’s position for a normal result is that your clinician sets the retesting schedule based on your age and your risk factors, rather than applying a fixed number to everybody.

That is less satisfying than an interval, and it is more accurate than one.

🩺 Physician Note: When two authoritative bodies publish different retesting intervals, the useful question is not which one to obey but what your own risk assessment looks like. Both sources make individual risk the deciding variable, which means the interval is meant to be a conversation rather than a lookup. Ask your primary care clinician: “Given my risk factors, do you want to recheck this in a year, or wait longer?”

If your result sat in that range and you want to know what usually happens next, results in the prediabetes range covers the follow-up path in detail — this section deliberately stops at the timing question.

What not to do with the number you just read

Four habits undo everything above, and the first is a risk this article’s own headline creates.

Don’t turn a minimum into a maximum

If you arrived here from a headline reading “twice a year” and stopped there, you have the floor without the condition attached to it. That is the most common way this guidance goes wrong, and it goes wrong in the worst possible direction: the reader who most needs quarterly monitoring is the one handed permission to test half as often.

The floor belongs to someone whose situation is stable. If your treatment changed, if you are not at your goal, or if your health status shifted, the twice-yearly figure was never yours.

Don’t let a home result reset your schedule

A result obtained outside your clinician’s ordering pathway does not replace a scheduled test. NIDDK states that results from tests run in an office or clinic — point-of-care tests — should not be used for diagnosis, and that when the A1C is used diagnostically the sample is drawn from a vein and sent to a lab using a certified method.

There is a separate reason not to treat an outside number as your next data point: your clinician cannot act on a result they cannot verify.

⚠️ Clinical Warning: This article will not point you toward a testing product to use between appointments, and the reason comes from our own sources rather than from a policy. NIDDK states that point-of-care A1C results should not be used for diagnosis, and specifies a venous sample analyzed by a certified laboratory method when the test is used diagnostically. A number obtained outside your clinician’s ordering pathway cannot substitute for one inside it, cannot be acted on with confidence, and does not change what your record shows. If you have already used one and the result concerned you, that is a reason to contact your clinician — not a reason to change your own schedule.

Don’t read a coverage limit as a clinical one

A screening cap is an insurance rule about a population. A testing interval is a clinical judgment about you. They are set by different bodies for different reasons, and the coverage rule itself provides for testing beyond its stated frequency where medical necessity is documented.

One more distinction that trips people up: a confirmatory repeat is not part of your routine cadence. NIDDK notes that if you have no symptoms but a test shows diabetes or prediabetes, you should have a repeat test on a different day to confirm it — that second test confirms the first, and it does not reset any twelve-month clock. When a result gets repeated covers that distinction as it applies across blood tests.

Finally, this article does not tell you that you are overdue. It tells you what the guidelines set and what conditions change them. Whether your own schedule is right is a judgment that needs your history, and your clinician has that and we do not.

Common questions about how often to test

Working out when yours is due

The practical version of everything above fits in two lines. If you have diabetes and you are meeting your goals with nothing recently changed, the published minimum is two A1C tests a year — and if you are not meeting them, or your treatment changed, or your health status shifted, it is about every three months.

Take the date of your last test to your next appointment along with a note of anything that has changed since. Then ask the clinician who manages your diabetes one question: “When do you want to check this next, and what would make you want it sooner?” That second half is the part worth writing down, because it is what tells you when to come back early rather than waiting for the calendar.

If a coverage limit has been raised with you, the rule itself provides for testing beyond its stated frequency when medical necessity is documented — that is a conversation with your clinician about the order, not an argument with your plan.

How this was made

About this content

How this article was put together: researched from recognised health sources, drafted with the help of AI tools, and edited by hand, with sources linked throughout.

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Sameer Patel — Founder & Editor

Researched and written from recognised health sources

Sameer Patel is the founder and editor of My Medicine Advisor. He is not a doctor or medical professional — before starting this site he worked in banking,…

Content on MyMedicineAdvisor is researched from recognised sources, drafted with AI assistance, and edited by hand, with sources linked so you can check them. It is general health education, not medical advice, and there is no clinical review panel.