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This information was reviewed and approved by Ann Hefel (1/31/2016).

What is a food challenge?
How do you get ready for the test?
What is done during the test?
How long will the test take?
How do you get to your test?

What is a food challenge?

Based on the history and allergy test results your doctor has suggested that a food challenge be performed as part of your evaluation at National Jewish Health. The purpose of a food challenge is to identify if you are allergic to a specific food and how much of the food it may take to cause a reaction.

Learn reasons to do food challenges


How do you get ready for the food challenge testing?

Please follow these directions when getting ready for this test.

  • Your doctor may ask you to bring in a specific food for the food challenge. Please bring the food the morning of the test.  You may also be asked to bring a favorite food in which to place the food to be challenged.

  • Usually you eat only the food being provided during the food challenge. Please discuss this with your nurse and do not eat other foods during the food challenge.

  • If you are sick, please call to cancel the food challenge. This includes cold symptoms, diarrhea or a stomach ache, a body rash or atopic dermatitis flare. The food challenge results may be hard to interpret if these are present. If you have any questions, please call to speak with a nurse. The number to call is 303.398.1355

  • If you are given a sedating antihistamine for a reaction during the food challenge, you may not be able to drive. Please make sure to have a family member or friend available to take you home in case this were to occur.

  • Please check in at the Front Desk at the time your test is scheduled.

The following medicines might affect the results of the food challenge and will need to be stopped before the testing is done unless your doctor tells you otherwise.

If the medicine is not stopped before the food challenge we may not be able to complete the challenge.

All antihistamines will affect the results of some of these tests and need to be stopped before the testing is done. If you have any concerns about stopping antihistamines please check with your doctor before you stop the medicine. If the medicine is not stopped before the test we may not be able to perform the test.

Stop these antihistamines for the length of time listed before your appointment at National Jewish Health:

Stop these oral antihistamines for 5 days before your appointment:

  • Claritin® (loratadine)
  • Allegra® (fexofenadine)
  • Clarinex® (desloratadine)
  • Zyrtec® (cetirizine)
  • Xyzal® (levoceterizine)

Stop these oral antihistmanines for 3 days before your appointment:

  • Actifed®, Dimetapp® (brompheniramine)
  • Atarax®, Vistaril® (hydroxyzine)
  • Benadryl® (diphenhydramine)
  • Chlortrimeton® (chlorpheniramine)
  • Phenergan® (promethazine)
  • Tavist®, Antihist® (clemastine)
  • Astelin®, Astepro®, Dymista® (nasal sprays)
  • Actifed®, Aller-Chlor®, Bromfed®, Drixoral®, Dura-tab®, Novafed-A®, ine-D®, Trinalin® (Combination medicines)

If you are taking an antihistamine that is not listed, ask your doctor.

Some antidepressants can also act as an antihistamine. Let your doctor know if you are on any antidepressants before the food challenge. Do not stop the antidepressant without discussing it with your doctor.

Stop these medicines the night before your appointment:

  • Singulair® (montelukast)
  • Accolate® (zafirlukast)

Stop these medicines the morning of your appointment:

  • Zyflo® (zileuton)
  • Tagamet® (cimetadine)
  • Zantac® (ranitidine)
  • Pepcid® (famotidine)
  • Axid® (nizatidine)

Continue to take all other medicines as you usually do.


What is done during the test?

You will check in to MIDC East. You may bring reading materials, a laptop or tablet to use during your food challenge. MIDC has wireless access for your technology devices.

You will begin the food challenge by eating a small amount of the suspected food. If the first dose is tolerated you will be given gradually increasing amounts of the food every 15 to 30 minutes until a normal meal-sized portion is eaten or the challenge is stopped because of symptoms or a reaction. You will be monitored closely during the food challenge by the nursing staff. Your doctor will be available to provide evaluation or treatment in case of any symptoms. 

Once the food challenge is done your doctor will discuss the results with you, answer your questions, and make recommendations.


How long will the food challenge take?

A single food challenge usually takes from 4-6 hours, but can take longer if you have a reaction. You should plan to spend the entire day at National Jewish Health. Sometimes more than one food may be challenged in a day, but this will be up to your doctor.


How do you get to your test?

Your food challenge will be scheduled in the MIDC. Check in at the Front Desk in at the time your test is scheduled. If you have questions please call 303.398.1355.

Get directions to and view a campus map of National Jewish Health.


This information has been approved by Ann Hefel, FNP, MS, RN (February 2016)