You have an A1C from last year and nothing was ever said about it: a blood test, a percentage sitting on a patient portal, no phone call afterward. Nobody told you the number was a problem and nobody told you it was fine. A1C results are read against a published scale of three bands, and the band a result falls in sets how often the test gets repeated after it. Hold your own result against those bands and the interval falls out of it — three years, or one.
What the middle band changes is the schedule. An A1C below 5.7% is normal, 5.7% to 6.4% is prediabetes, and 6.5% or above is diabetes, so 6.0% sits in the middle one. A normal result is retested every 3 years, and someone diagnosed with prediabetes is tested every year. A single middle-band number is not that diagnosis yet — one result does not make one — so what a year-old 6.0% earns first is the repeat that confirms or clears it, and the booking starts with somebody asking for it.
Which band your result falls in
Three different blood tests sort people into the same three bands NIDDK publishes, and each test has its own numbers, so a result means nothing until you know which one produced it. An A1C comes back as a percentage. A fasting plasma glucose and an oral glucose tolerance test both come back in mg/dL.
| Result | A1C | Fasting plasma glucose | Oral glucose tolerance test |
|---|---|---|---|
| Normal | Below 5.7% | 99 mg/dL or below | 139 mg/dL or below |
| Prediabetes | 5.7% to 6.4% | 100 to 125 mg/dL | 140 to 199 mg/dL |
| Diabetes | 6.5% or above | 126 mg/dL or above | 200 mg/dL or above |
A single result in the prediabetes or diabetes column, in someone with no symptoms, gets confirmed before it counts as a diagnosis: a repeat test on a different day, using the A1C again or one of the other tests. So check the record for a second test after yours; if none followed, the number is still unconfirmed.
An A1C is also less reliable for some people than a table of bands suggests. Iron-deficiency anemia can push the number falsely high, kidney failure and liver disease can distort it, and for people of African, Mediterranean or Southeast Asian descent, or with sickle cell anemia or a thalassemia in the family, an A1C can be unreliable for diagnosing or monitoring diabetes. Any of those is worth naming out loud when you ask for a test, because it changes which test is worth running.
When the next test is due
The band your result sat in sets when the next one is due. Adults and children whose diabetes test results are normal are retested every 3 years; adults and children diagnosed with prediabetes are tested for type 2 diabetes every year.
Put your own result and its date against that. A 6.0% drawn in the middle of last year is a middle-band result whose annual retest falls due around the anniversary of the draw, which is now rather than at some future appointment. If nobody ever confirmed it with a second test, say so when you ask — a test that confirms last year's result and a test that follows up a confirmed one are two different orders, and the number alone does not say which is needed.
Symptoms move it off the calendar altogether. Among the symptoms of diabetes are increased urination, feeling very thirsty, feeling very hungry even after eating, blurred vision, fatigue, sores that do not heal and frequent infections. With any of those, talk with your primary health care professional about the symptoms you are having and ask whether you need to be tested — a conversation this week, rather than a date a year out.
How to get the test ordered
A clinician orders the test, and the reason to ask for one is a risk-factor list rather than a symptom you have to produce. CDC's instruction is to ask your doctor about getting tested for prediabetes or type 2 diabetes if any of its risk factors apply. Among them:
- Having overweight or obesity
- Being age 45 or older
- Having a parent or sibling with type 2 diabetes
- Being physically active less than 3 times a week
- Having non-alcoholic fatty liver disease
- Having had gestational diabetes, or having given birth to a baby who weighed over 9 pounds
- Being an African American, Hispanic or Latino, American Indian or Alaska Native person; some Pacific Islander and Asian American people also carry higher risk
Which test you ask for decides what the appointment has to look like. An A1C needs no fasting and can be drawn at any time of day, so it rides along with blood work you already have booked. A fasting plasma glucose and an oral glucose tolerance test each need an overnight fast, which means a morning slot and an empty stomach on the way in. Ask for the A1C by name if getting to a lab twice is the hard part.
What to do with the number you already have
- Find the result and its date on your portal or in the lab report, and note which test it was — A1C, fasting glucose, or a glucose tolerance test.
- Read it against the table above and write down the band. Middle band plus a date more than a year old means the retest is due.
- Message or call your primary care clinician with three facts: the result, the date it was drawn, and whether a second test ever confirmed it. Ask whether a retest is due now.
- Say in the same message if you have iron-deficiency anemia, kidney or liver disease, or sickle cell anemia or thalassemia in the family, because those change how reliable an A1C is for you.
- Report increased urination, thirst, blurred vision, fatigue or slow-healing sores if you have any, since those change the timing from an interval to now.
An A1C describes the three months before the blood was drawn. Which band you are in this year is settled by one more draw, and the draw needs somebody to order it.
