Getting Ready for Your Fasting Blood Draw
Your provider has asked that you perform the blood test(s) circled below:
Fasting Glucose Glucose Tolerance Test* Lipid Panel Cryoglobulin
(8+ hours) (8+ hours) (10+ hours) (6+ hours)
These tests require you to be fasting prior to the blood draw. *Fasting is NOT required for 1-
hour glucose challenge for gestational diabetes.
What is fasting?
Fasting means you don’t eat or drink
anything but water for a defined period of
time before your blood draw.
You also shouldn’t smoke, chew gum (even
sugarless) or exercise. These things can
affect your digestion, which can affect your
Take your prescription medicines unless
your doctor tells you to skip them. Ask your
provider before you take over-the-counter
Why do I have to fast?
Nutrients in food and drinks go into your
bloodstream and can change things
measured by tests, which will affect your
test results. Fasting ensures the results from
the test are accurate.
What if I slip up?
If you make a mistake and eat or drink
something besides water, please tell the
person drawing your blood. Your provider
may change your test orders so your blood
can be drawn and he/she can read those tests
correctly. For the best test results, he/she
may ask you to return when you are fasting.
When can I eat or drink again?
Once your blood has been drawn, your fast
is over! Please feel free to bring a snack and
drink with you to your lab visit so you can
eat as soon as you can after your blood
Your health care team may have given you this information as part of your care. If so, please use it and call if you
have any questions. If this information was not given to you as part of your care, please check with your doctor.
This is not medical advice. This is not to be used for diagnosis or treatment of any medical condition. Because
each person’s health needs are different, you should talk with your doctor or others on your health care team
when using this information. If you have an emergency, please call 911. Copyright © 5/2017 University of
Wisconsin Hospitals and Clinics Authority. All rights reserved. Produced by the Department of Nursing. HF#7979