How Do You Know If You Have Diabetes?

May 2004

Return to About Diabetes

Some people are at higher risk for developing diabetes.

You might be at risk for developing diabetes if:

• Your parents, or sister or brother have diabetes.
• You are an African American, Latino, Native American, Asian American or Pacific Islander.
• You are overweight.

The risk for developing diabetes also increases with age.

Symptoms of diabetes include:

• Frequent urination
• Excessive thirst
• Extreme hunger
• Unusual weight loss
• Increased fatigue
• Irritability
• Blurry vision

However, some people never have symptoms of diabetes.

The only way to know if you have diabetes is to see your doctor. A blood test is needed to diagnose diabetes.

If you have symptoms of diabetes, your doctor may have a blood test completed right away, whether you’ve eaten recently or not (called non-fasting or random). If your blood glucose test is over 200 mg/dl, you may have diabetes.

If your doctor asks for a fasting blood glucose, and your level is over 126 mg/dl, you may have diabetes. The “cut-off” is lower if you’ve been fasting because food makes the blood glucose rise.

Your doctor may want you to have an oral glucose tolerance test instead of just a blood test. The doctor will give you a sweet solution to drink (75 grams of glucose) and then your blood will be tested after 2 hours. If this blood glucose is over 200 mg/dl, you may have diabetes.

If your tests are borderline, the test should be repeated on another day.

If you are at risk, have symptoms of diabetes, or any suspicions that you may have diabetes, talk to your doctor about having your blood glucose tested. Remember, this information doesn’t replace any that your doctor may have given you or spoken to you about.