Glucose Tolerance Test

This is a test to see how your body processes carbohydrates. This test is often done to check patients for diabetes or the possibility of developing it.

PREPARATION FOR TEST

You should have nothing to eat or drink 12 hours before the test. You will be given a form of sugar (glucose) and then blood samples will be drawn from your vein to determine the level of sugar in your blood. Alternatively, blood may be drawn from your finger for testing. You should not smoke or exercise during the test.

NORMAL FINDINGS

  • Fasting: 70-115 mg/dL

  • 30 minutes: less than 200 mg/dL

  • 1 hour: less than 200 mg/dL

  • 2 hours: less than 140 mg/dL

  • 3 hours: 70-115 mg/dL

  • 4 hours: 70-115 mg/dL

Ranges for normal findings may vary among different laboratories and hospitals. You should always check with your doctor after having lab work or other tests done to discuss the meaning of your test results and whether your values are considered within normal limits.

MEANING OF TEST

Your caregiver will go over the test results with you and discuss the importance and meaning of your results, as well as treatment options and the need for additional tests.

OBTAINING THE TEST RESULTS

It is your responsibility to obtain your test results. Ask the lab or department performing the test when and how you will get your results.