An A1C of 5.7% to 6.4% is considered prediabetes. Anything below 5.7% is normal, and an A1C of 6.5% or higher on two separate tests indicates type 2 diabetes. If your result landed somewhere in that middle range, you’re in a zone where blood sugar is elevated but not yet high enough for a diabetes diagnosis.
What the A1C Test Actually Measures
The A1C test reflects your average blood sugar over the past two to three months. It works because glucose in your bloodstream naturally sticks to hemoglobin, a protein inside red blood cells. The more sugar circulating in your blood, the more hemoglobin gets coated. Since red blood cells live about three months before being replaced, the test captures a rolling average rather than a single snapshot.
This makes A1C more stable than a fasting glucose test, which only tells you what your blood sugar is doing on the morning of the draw. You don’t need to fast before an A1C test, and a single blood sample is all that’s needed.
What Each A1C Range Means
- Below 5.7%: Normal blood sugar regulation.
- 5.7% to 6.4%: Prediabetes. Your body is starting to have trouble managing glucose efficiently.
- 6.5% or higher: Diabetes (confirmed with a repeat test).
The difference between 5.7% and 6.4% matters. Someone at 5.8% has mildly elevated blood sugar and plenty of room to course-correct. Someone at 6.3% is close to the diabetes threshold and likely has more significant insulin resistance. Your doctor may approach these two scenarios differently in terms of how aggressively they recommend lifestyle changes or follow-up testing.
How Likely Prediabetes Is to Become Diabetes
Prediabetes is not a guarantee of diabetes, but the odds aren’t trivial. Without intervention, people with prediabetes progress to type 2 diabetes at a rate of 5% to 10% per year. Over a lifetime, roughly 70% of people with prediabetes will eventually develop diabetes if nothing changes. Those numbers sound alarming, but they also highlight the window you have to act. Prediabetes can stay stable for years, and in many cases it can be reversed entirely.
Lowering Your A1C Back to Normal
The most well-studied approach comes from the CDC’s Diabetes Prevention Program, which focuses on two targets: losing 5% to 7% of your body weight and getting regular moderate physical activity. For someone who weighs 200 pounds, that means losing 10 to 14 pounds. That’s it. The weight loss doesn’t need to be dramatic to shift your A1C back below 5.7%.
The physical activity component centers on consistent, moderate-intensity movement. Think brisk walking, cycling, or swimming. The program is structured over 12 months and emphasizes daily tracking of activity minutes to build habits that stick. The combination of modest weight loss and regular exercise has been shown to cut the risk of progressing to diabetes by more than half.
Diet changes that help most are the ones that reduce blood sugar spikes: cutting back on refined carbohydrates and sugary drinks, eating more fiber, and spreading meals more evenly throughout the day rather than eating one or two large ones. These adjustments don’t require a specific diet plan, just a shift in patterns.
Who Should Get Screened
The U.S. Preventive Services Task Force recommends A1C screening for adults aged 35 to 70 who are overweight or obese (a BMI of 25 or higher). If you’re Asian American, the recommended screening threshold drops to a BMI of 23, because type 2 diabetes tends to develop at lower body weights in this population. Earlier screening is also recommended for Black, Hispanic/Latino, American Indian/Alaska Native, and Native Hawaiian/Pacific Islander adults, who face higher rates of diabetes overall.
If your first A1C comes back normal, repeat testing every three years is typical. If you’re in the prediabetes range, your doctor will likely recheck annually to see whether your numbers are holding steady, improving, or trending upward.
When A1C Results Can Be Misleading
Because the test depends on hemoglobin, anything that changes your red blood cells can throw off the reading. Iron deficiency anemia, sickle cell trait, recent blood loss, and blood transfusions can all produce A1C results that don’t accurately reflect your true average blood sugar. Pregnancy and kidney disease can also affect results. If you have any of these conditions, your doctor may rely on fasting glucose or an oral glucose tolerance test instead. A fasting glucose of 100 to 125 mg/dL corresponds roughly to the same prediabetes range as an A1C of 5.7% to 6.4%.