Oral Glucose Tolerance Test (OGTT)

Oral Glucose Tolerance Test (OGTT) – Sugar Tolerance Test

The oral glucose tolerance test (OGTT) is a simple blood test used to assess how well your body processes sugar. It is an important examination for the early detection of diabetes or impaired glucose metabolism.

Preparation – Important Information

To ensure accurate results, please follow these instructions carefully:

3 days before the test

  • Eat a normal diet, including carbohydrates (bread, pasta, rice, potatoes)
  • Do not follow a low-carb or restrictive diet
  • Maintain your usual level of physical activity

Evening before the test (from approx. 6:00 PM)

  • Do not eat any more food
  • Only water is allowed
  • No coffee, alcohol, or smoking
  • Fasting period should be 12–16 hours

On the morning of the test

  • Come fasting (no food or drinks)
  • A small glass of water is allowed if necessary
  • Arrive at the practice between 7:30 and 8:30 AM

General notes

  • Do not take the test if you are acutely ill (fever, infections, gastrointestinal illness)
  • Bring your medications with you (you may take them after the test if needed)
  • Plan approximately 2 to 2.5 hours for the appointment
  • Bring something to read, as you will need to rest during the test

Test Procedure – Step by Step

  1. First blood sample: Measurement of fasting blood glucose
  2. Glucose drink: You will drink a solution containing 75 g of glucose in 300 ml of water within about 5 minutes
  3. Waiting period: You will remain seated in the waiting area for 2 hours
    • No physical activity
    • No eating or drinking
    • No smoking
  4. Further blood samples: Blood is taken after 60 minutes and 120 minutes
  5. End of test: After 2 hours, the test is complete and you may leave or wait for consultation

After the Test

You may eat and drink normally after the examination. Any medication can also be taken again as usual.

The results will be discussed with you in a separate consultation.

Do you have any further questions?

If you have any questions about preparation or if you fall ill, please contact our practice before your appointment.