A prediabetic A1C falls between 5.7% and 6.4%. This range means your average blood sugar over the past three months is higher than normal but not yet high enough to qualify as type 2 diabetes. Below 5.7% is considered normal, and 6.5% or above on two separate tests indicates diabetes. More than 115 million American adults have prediabetes, and 8 in 10 of them don’t know it, largely because the condition rarely causes obvious symptoms.
What the A1C Test Actually Measures
When sugar circulates in your bloodstream, some of it latches onto hemoglobin, the protein inside red blood cells that carries oxygen. Everyone has a certain amount of sugar stuck to their hemoglobin, but the more sugar in your blood, the more that accumulates on those cells. The A1C test measures the percentage of red blood cells coated with sugar.
Because red blood cells live for roughly three months before your body replaces them, the A1C result reflects your average blood sugar over that entire window. That makes it more useful than a single finger-stick reading, which only captures a snapshot of one moment. You don’t need to fast before an A1C test, either, which is why many doctors prefer it as a screening tool.
Prediabetic vs. Normal vs. Diabetic Ranges
- Normal: below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or higher (confirmed on a repeat test)
A result of 5.7% sits right at the threshold, so if your number lands there, your doctor may retest in a few months or order additional blood work to confirm the picture. Someone at 6.3% or 6.4% is at the upper edge of prediabetes and faces a higher near-term risk of crossing into diabetes territory.
Other Tests That Diagnose Prediabetes
A1C isn’t the only way to identify prediabetes. A fasting plasma glucose test measures your blood sugar after you haven’t eaten for at least eight hours. A result between 100 and 125 mg/dL falls in the prediabetic range. There’s also the oral glucose tolerance test, where you drink a sugary solution and have your blood drawn two hours later. A reading between 140 and 199 mg/dL at the two-hour mark indicates prediabetes.
These tests measure slightly different things. A1C gives a three-month average, fasting glucose shows your baseline sugar level, and the glucose tolerance test reveals how efficiently your body clears sugar after a meal. Sometimes results from different tests don’t perfectly agree. If one test comes back borderline, your doctor may use a second type to get a fuller picture.
Why Prediabetes Matters
Prediabetes is not a harmless in-between stage. Around 5 to 10% of people with prediabetes progress to type 2 diabetes each year, though the rate varies depending on other risk factors like weight, family history, and activity level. Without changes, that annual risk compounds over time.
Damage to your cardiovascular system and kidneys can begin before blood sugar officially reaches the diabetic range. Prediabetes has been linked to harm to blood vessels and to silent heart attacks, the kind that cause measurable cardiac damage without the classic chest-clutching symptoms. This is one reason screening matters even when you feel fine.
Symptoms You Might Notice
Most people with prediabetes have no symptoms at all, which is why the condition goes undetected so often. When signs do appear, they tend to be subtle: increased thirst, more frequent urination, fatigue, or slightly blurred vision. Some people develop patches of darkened, velvety skin on the neck, armpits, or groin. These skin changes signal that your body is producing extra insulin to compensate for rising blood sugar, and they can be one of the earliest visible clues.
Lowering Your A1C Back to Normal
Prediabetes is reversible. The landmark Diabetes Prevention Program trial found that two specific targets cut the risk of developing type 2 diabetes by 58%: losing 7% of your body weight and getting 150 minutes of moderate physical activity per week. For someone who weighs 200 pounds, that’s 14 pounds. For activity, 150 minutes breaks down to about 30 minutes of brisk walking five days a week.
The weight loss goal matters more in the early phase. Excess body fat, especially around the midsection, makes your cells more resistant to insulin. Losing even a modest amount improves how your body processes sugar, often enough to bring an A1C of 5.8% or 5.9% back below 5.7%. The exercise goal works through a different mechanism: active muscles pull sugar from the bloodstream more efficiently, with or without insulin’s help, lowering your overall average.
Dietary changes that support these goals include reducing refined carbohydrates and sugary drinks, increasing fiber from vegetables and whole grains, and eating protein with each meal to slow the spike in blood sugar after eating. These aren’t temporary fixes. The people in the prevention trial who maintained their weight loss and activity level continued to see lower diabetes risk years after the study ended.
How Often to Retest
If your A1C comes back in the prediabetic range, most guidelines recommend retesting at least once a year. If your result was on the higher end (6.0% to 6.4%) or you have additional risk factors like a strong family history or obesity, your doctor may want to check every six months. Tracking your A1C over time shows whether your lifestyle changes are working or whether your numbers are creeping upward. A single test tells you where you are. Repeated tests tell you which direction you’re heading.