A Toronto doctor is warning people about testing to determine whether a person has allergies, sensitivities or intolerance to certain foods.

Dr. Elana Lavine of Humber River Regional Hospital says some of these tests, which can cost hundreds of dollars, can be misused and misinterpreted.

Writing in the Canadian Medical Association Journal, Lavine says in some cases, readings are interpreted to mean an intolerance to a food or foods when in fact the reverse is actually true.

She says both traditional physicians and holistic medicine practitioners may offer blood testing to diagnose adverse reactions to food, and unstandardized tests can be bought from a variety of health-care providers as well as some pharmacies.

Lavine says doctors should tell their patients about the controversies surrounding testing for food sensitivities, including the fact that there is no proven role for using readings of antibodies called IgG in testing for food allergies.

Recent position papers from European and U.S. allergy and immunology societies also emphasize the limitations and potential misuse of testing looking for IgG4 antibodies, saying these tests are not appropriate for making a diagnosis of food allergy.