A1c Basics for People With Type 2 Diabetes
An A1c below 5.7 percent is considered normal for someone without diabetes. An A1c of 6.5 percent or higher qualifies as diabetes. Anything in between is classified as prediabetes. Keep in mind that additional testing is almost always necessary to confirm a diagnosis of type 2 diabetes; healthcare providers almost never rely on a single test to make the call. If your A1c comes back high, your healthcare provider might repeat the test or try a fasting blood glucose test or an oral glucose tolerance test to confirm the results.
Keep in mind that up until 2009, A1c was not considered an acceptable test for screening or diagnosing diabetes due to differences among the various versions of the test. However, now that the tests are standardized, the A1c is considered acceptable for such uses.
There are many different terms you might hear in reference to the same A1c test, including:
- Hemoglobin A1c
- Glycosylated hemoglobin
- Glycated hemoglobin
All of these terms mean the same thing; they're all just different names for the same type of test.
Critics of A1c testing (especially screening) often point out that it may not be wise to use an indirect measurement for screening and monitoring. In some people, the A1c test may be unreliable because it may not accurately reflect blood glucose numbers. This may be true if you don't have the typical form of hemoglobin -- that is, you have a "variant" form of hemoglobin. You might have a hemoglobin variant if:
- You are of African, Mediterranean, or Southeast Asian heritage
- You have a family history of sickle cell anemia
- Your A1c results don't match up with your blood glucose monitoring
- Your A1c is very high
- Your A1c results fluctuate wildly.
Basically, if your A1c result is surprising or just doesn't make sense, you might have a hemoglobin variant. Your doctor can order a blood test to check which forms of hemoglobin you have. What to do if you have one of the variants? There are several different A1c tests, and some can still be used with some of the variants. Your doctor will need to check to make sure.
Kidney failure, anemia, and recovery from a large blood loss can also make the A1c test less reliable.