Normal Values:

Normal blood values for a 75-gram oral glucose tolerance test used to check for type 2 diabetes:

• Fasting: 60 -100 mg/dL
• 1 hour: less than 200 mg/dL
• 2 hours: less than 140 mg/dL. Between 140 - 200 mg/dL is considered impaired glucose tolerance (sometimes called "prediabetes"). This group is at increased risk for developing diabetes. Greater than 200 mg/dL is a sign of diabetes mellitus.

Normal blood values for a 50-gram oral glucose tolerance test used to screen for gestational diabetes:

• 1 hour: equal to or less than 140 mg/dL

Normal blood values for a 100-gram oral glucose tolerance test used to screen for gestational diabetes:

• Fasting: less than 95 mg/dL
• 1 hour: less than 180 mg/dL
• 2 hour: less than 155 mg/dL
• 3 hour: less than 140 mg/dL

Note: mg/dL = milligrams per deciliter

Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

What abnormal results mean:

Greater than normal levels of glucose may mean you have diabetes or gestational diabetes.

However, high glucose levels may be related to another medical problem (for example, Cushing syndrome).