Cystic fibrosis - CF - Glucose tolerance test

Key points below

Cystic fibrosis (CF)

What is a Glucose tolerance test?

The test is done to find out how the body handles glucose (sugar). If the body does not handle glucose like it should, it can cause diabetes. Untreated diabetes can lead to serious health problems. It can also make symptoms of CF worse.

What is Diabetes?

Diabetes is a disorder that affects the way the body uses food for energy. Insulin is a hormone made in the pancreas. It helps move glucose out of the blood stream and into the cells. Without insulin, too much sugar stays in the blood.

With CF, the normal thin mucus that coats and protects the nose, throat, mouth, and lungs gets thick and sticky. The thick mucus clogs the pancreas. It keeps the body from making insulin normally. This leads to CF diabetes.

How is this test done?

Three days before the test, you should eat 3 to 4 servings of carbohydrates (carbs) at each meal. This helps the body prepare for the test. Foods high in carbs include: pizza, bread, cereal, rice, crackers, fruit, juice, milk, yogurt, beans, pasta, potatoes, and corn. Sweet foods and snack foods like soda, juice drinks, syrup, honey, cake, cookies, donuts, pudding, candy, and chips are also high in carbs and fats.

For 10 hours before the test you should not eat, but please drink a lot of water. If you eat or drink anything besides water, you should talk to your provider before starting the test.
The glucose tolerance test includes 3 blood tests. Please go to the Laboratory on the 2nd floor of the Clinics Building to have the first blood test done.
After the first blood test, come to CF clinic. A sweet drink will be given in clinic.
One hour after drinking the sweet drink, the second blood test will be done in the lab.
Two hours after drinking the sweet drink, the last blood test will be done in the lab.

Special Information

People with cystic fibrosis should have this test done once a year starting at 10 years old.
This test cannot be done on someone who is sick. Illness can affect the test results. Please call the CF clinic at 414-266-6730 to cancel the test. You should still plan to come to your CF clinic appointment.
If it is a problem to schedule the blood test during the clinic visit, the test can be done at a lab closer to your home. Ask your provider for lab orders.

ALERT

Call your child’s doctor, nurse, or clinic if you have any questions or concerns or if your child has special health care needs that were not covered by this information.