SATURDAY, Nov. 5 (HealthDay News) -- Too few American doctors use oral food challenges to diagnose food allergies even though this type of test is considered the gold standard, according to a new study.

In an oral food challenge, a patient consumes foods to see if it causes an allergic reaction. This is done under close medical supervision.

Researchers surveyed about 40,000 children and identified 3,339 cases of food allergy. However, only 61.5 percent of the cases were formally diagnosed by a doctor and only about 15 percent of those children underwent an oral food challenge.

Children with severe symptoms such as anaphylaxis (life-threatening allergic reaction), wheezing, breathing difficulties and low blood pressure were most likely to be diagnosed by a doctor and most likely to undergo an oral food challenge.

The findings that many children with food allergy are not diagnosed by a doctor and not given a food challenge suggest that food allergy may be underdiagnosed in the United States, the researchers concluded.

The study was scheduled to be presented at this week's annual meeting of the American College of Allergy, Asthma and Immunology in Boston.

"Oral food challenge provides a definitive diagnosis which is critical to providing proper disease management and prevents unnecessary avoidance of certain foods," Dr. Ruchi Gupta of Children's Memorial Hospital, in Chicago, said in an ACAAI news release. "Physicians may not be conducting the test due to the length of time it takes, three to six hours, and the low reimbursement for a food challenge."

Because this study was presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.

In suspected cases of food allergy, patients should be referred to an allergist, according to the ACAAI.

More information

The U.S. National Institute of Allergy and Infectious Diseases has more about food allergy.