4 Common Diabetes Tests

Catching diabetes early can make a big difference for your long-term health. Because symptoms often develop slowly, regular screenings are one of the best ways to spot prediabetes or diabetes before complications start. These tests are simple, quick and can give you peace of mind about where your blood sugar stands.

Diabetes Screenings: What to Expect

Diabetes is the 8th leading cause of death in the U.S. and can lead to health problems like heart disease and joint issues. The good news is that early detection gives you more options to protect your health. Here are the four most common diabetes screenings and what your results mean:

1. A1C Test

The A1C test shows your average blood sugar levels over the past three months. It’s the most common test used to diagnose both Type 1 and Type 2 diabetes and is also used to monitor people already living with diabetes. A blood sample is taken, and results are usually ready within 24 hours.

How to read your numbers: 

• Below 5.7%: Normal
• 5.7%–6.4%: Prediabetes
• 6.5% and above: Diabetes

2. Fasting Blood Sugar Test

This test measures your blood sugar after not eating or drinking anything (except water) for at least eight hours, usually first thing in the morning.

How to read your numbers: 

• 70–100 mg/dL: Normal
• 100–126 mg/dL: Prediabetes
• 126 mg/dL and above: Diabetes

3. Random Blood Sugar Test

A random blood sugar (RBS) test checks your blood sugar at any time of day — no fasting required. It can be done in your doctor’s office, a lab, or even at home with a finger-prick device and glucometer. This test only detects diabetes, not prediabetes.

How to read your numbers: 

• 200 mg/dL and above: Diabetes (especially if you have symptoms such as blurry vision, increased thirst, frequent urination or unexplained weight loss)

4. Glucose Tolerance Test

This test measures how your body processes sugar. It’s often used to check for Type 2 diabetes and is also adapted to screen for gestational diabetes during pregnancy. After fasting, your blood is tested, then you drink a sweet glucose solution. Two hours later, your blood is tested again.

How to read your numbers (after two hours): 

• 140 mg/dL or below: Normal
• 140–199 mg/dL: Prediabetes
• 200 mg/dL and above: Diabetes

When to Get Screened

The American Diabetes Association recommends that adults age 45 and older get tested for Type 2 diabetes every three years. If you’re overweight or obese, your doctor may suggest starting earlier and testing more often.

If you’re concerned about your risk, talk with your doctor about whether you should be screened and what your results mean. Together, you can also discuss lifestyle changes and preventive steps to help you stay healthy. To learn more about diabetes, reach out to our Health Education Resource Centers.