Prediabetes: signs, tests and how to lower your risk

In short

• Prediabetes is blood sugar that is higher than normal but not high enough for a diagnosis of type 2 diabetes.
• There are usually no clear symptoms, so it often goes undetected until type 2 diabetes appears.
• A simple blood sugar test, such as the A1C, can show whether you have it.
• The CDC-led National Diabetes Prevention Program can lower the risk of type 2 diabetes by 58 percent, or 71 percent for people over 60.
• Prediabetes also raises the risk of heart disease and stroke, so blood pressure and cholesterol deserve attention too.

What prediabetes is

It develops when your cells stop responding normally to insulin, a problem called insulin resistance. The pancreas makes more insulin to compensate, and eventually it may not be able to make enough to keep blood sugar in check. Insulin resistance can also contribute to weight gain.

Prediabetes is not a little bit of diabetes and not a verdict. It is a stage at which what you do still matters a great deal.

Which tests find it

1. A1CMeasures your average blood sugar over the past 3 months. It is a blood sample taken at a doctor's office or lab, and fasting is not required.
2. Fasting plasma glucoseMeasures blood sugar after you have not eaten for a set time before the draw. Your provider will tell you how to prepare.
3. Oral glucose tolerance testMeasures blood sugar after you drink a glucose solution. It takes longer and costs more, so it is used less often.

Your provider interprets the numbers. Several conditions can falsely raise or lower an A1C result, including severe anemia, kidney failure, liver disease, certain blood disorders, some medicines, blood loss or transfusion, and early or late pregnancy, so tell your provider if any apply to you.

Who should be tested

• Adults aged 35 or older, or those with overweight or obesity and other risk factors.
• A parent, brother or sister with type 2 diabetes.
• Being physically active less than three times a week.
• A history of gestational diabetes, or having had a baby weighing 9 pounds or more.
• Polycystic ovary syndrome, sleep apnea or other conditions listed by NIDDK.
• Long-term use of certain medicines, such as glucocorticoids and some antipsychotics.
• Being African American, Hispanic or Latino, American Indian, Alaska Native, Pacific Islander, or some Asian American groups.

NIDDK adds that when risk factors are present but prediabetes is not found, testing is repeated at least every 3 years, and when prediabetes is found, testing for type 2 diabetes is done yearly. Children with overweight or obesity typically begin testing at age 10 or at puberty. Darkened patches of skin on the neck, armpits or groin can be a sign worth mentioning to your provider.

What works: the lifestyle program

Lifestyle changes are the most effective way to prevent or delay type 2 diabetes. The CDC's program targets are modest and concrete.

1. Lose about 5 to 7 percent of body weightThat is about 10 to 14 pounds for a person who weighs 200 pounds. Losing this amount reduced diabetes risk in the Diabetes Prevention Program.
2. Get at least 150 minutes of activity a weekBrisk walking counts: 30 minutes, five days a week.
3. Sleep enoughNIDDK lists getting enough sleep among the lifestyle changes.
4. Do not smokeSmoking and secondhand smoke are listed as risk factors, and WHO includes not using tobacco in diabetes prevention.

Food without extreme diets

WHO advice for preventing type 2 diabetes is a healthy diet that limits sugar and saturated fat, together with a healthy weight and regular activity. NIDDK simply lists eating healthy foods and drinks.

• Make vegetables, whole grains, beans, lean protein and nuts the base of your plate.
• Swap sugary drinks for water.
• Cut back on sweets and heavily processed foods.
• Choose a pattern you can keep for years instead of a crash diet.

Do you need medicine?

Health care professionals may prescribe metformin to manage blood glucose and prevent type 2 diabetes. In the Diabetes Prevention Program it delayed type 2 diabetes and worked best for women with a history of gestational diabetes, younger adults and people with obesity. That is a decision for you and your provider, to be made alongside lifestyle changes, never instead of them.

Do not stop or change a prescribed medicine on your own, and tell your provider about any supplements you use.

Follow-up

If prediabetes is found, the CDC says your doctor will likely recommend repeating the A1C every 1 to 2 years, while NIDDK says testing for type 2 diabetes yearly. Ask which schedule your provider wants. Specific goals are easier to follow than vague ones, such as walking 30 minutes five days a week or swapping soda for water.

Red flags

Prediabetes itself is not an emergency. Call 911 or go to an emergency department for severe vomiting with stomach pain, confusion or fainting, especially with intense thirst, frequent urination and weight loss, as these can signal very high blood sugar.

See your provider promptly for increased thirst and hunger, frequent urination, unexplained weight loss, blurry vision, slow-healing cuts or sores, or numbness or tingling in the hands or feet. These are common symptoms of diabetes, and they are often mild and can go unnoticed for years.

Questions and answers

Sources

1. CDC — Prediabetes: prevent type 2 diabetes
2. CDC — A1C test for diabetes and prediabetes
3. CDC — Diabetes signs and symptoms
4. NIDDK — Prediabetes and insulin resistance
5. WHO — Diabetes fact sheet

Sources checked on 29 October 2026.