Do I Need a Blood Sugar Test?

Doctors say the screening is essential, yet many adults skip it

Sari Harrar,

AARP

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Published January 22, 2026

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If you haven’t had a recent blood sugar test for diabetes or prediabetes, you’re not alone: Nearly half of U.S. adults haven’t. But doctors warn that skipping the routine screening can have serious consequences.

That’s because type 2 diabetes and prediabetes — a condition where blood sugar levels are above normal but not high enough to be called diabetes — are often symptomless, so testing is the only way to know your risk.

About 1 in 3 U.S. adults have prediabetes, and nearly 90 percent of those people don’t know they have it, according to the Centers for Disease Control and Prevention (CDC). What’s more, the condition becomes more common with age. Roughly half of adults 65 and older have prediabetes, the CDC says.

“Everyone should know their blood sugar number, the way you know your blood pressure or cholesterol,” says endocrinologist Dr. Samuel Dagogo-Jack, a professor at the University of Tennessee’s College of Medicine.

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If your numbers are higher than normal, lifestyle modifications, such as changes to your diet and exercise routine, can delay or even reverse a diagnosis. If left untreated, prediabetes can put you at risk for several health complications, including heart and kidney damage. Here are three things to know about getting a blood sugar test.

1. There’s more than one type of test

There are two widely used screening tests for high blood sugar.

The fasting plasma glucose test (FPG) usually requires an overnight fast as well as a blood draw, and a wait of several hours or days for lab results. The FPG gives you a “moment in time” snapshot of your blood sugar, yet it is still considered highly accurate for finding diabetes and prediabetes.

According to the CDC, a normal reading for this test is 99 milligrams per deciliter (mg/dL) or lower; prediabetes is 100-125 mg/dL; and diabetes is 126 mg/dL or higher.

The A1c test is another option, and experts say it has several key advantages. You don’t have to fast beforehand, it requires just a few drops of blood and results are usually available in minutes; they reflect your average blood sugar over two to three months.

A normal reading on this test is below 5.7 percent; prediabetes is 5.7-6.4 percent; diabetes is 6.5 or above.

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The oral glucose tolerance test is used less often and is the most time-consuming: You fast overnight, then drink a sugary beverage at a lab or doctor’s office. Your blood is drawn beforehand and two hours after the drink to measure how efficiently your body absorbs blood sugar.

At two hours, a normal reading is 140 mg/dL or below; prediabetes is 140-199 mg/dL; diabetes is 200 mg/dL or above.

2. The screening should be routine for most adults

Experts recommend adults age 35 and older be screened for diabetes at least once every three years. If you have prediabetes, you’re encouraged to check your blood sugar levels every year.

“You’ll want to know how any lifestyle changes you’re making are affecting your blood sugar,” Dagogo-Jack says.

Recent research published in Cardiovascular Diabetology–Endocrinology Reports found that adults with prediabetes who engaged in at least 150 weekly minutes of moderate-intensity exercise significantly reduced their risk of progressing to diabetes.

If you have type 2 diabetes, follow your doctor’s recommendations for periodic checks and at-home monitoring.

3. It’s often covered by insurance

Since 2024, Medicare Part B has covered A1c tests up to twice a year for those at risk for type 2 diabetes. That includes most Medicare beneficiaries: You’re considered to be at risk if you’re age 65 or older and overweight, have a family history of diabetes or had diabetes during pregnancy, according to the Centers for Medicare & Medicaid Services.

Most private health plans cover the testing, too, though it’s always a good idea to check with your provider about the specifics of your coverage.

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