Food-Reaction Testing: Why an IgG Panel Is Not an Allergy Shortcut

A broad food-IgG panel is not a validated shortcut to diagnosing food allergy or intolerance. The American Academy of Allergy, Asthma & Immunology advises against using food-IgG testing for that purpose. The useful next step after a suspected food reaction is an assessment based on what happened, not a larger list of foods to exclude.

Begin with the reaction history

Record the food, approximate amount, timing, symptoms, and whether the event has happened before. Bring product labels when relevant. Do not deliberately repeat a suspected serious reaction to improve your notes.

A clinician may choose targeted allergy testing, including specific IgE tests, based on the history. Even an IgE result needs interpretation; a positive laboratory result alone does not prove that eating the food causes symptoms.

Compare the claim, not the panel size

Ask what the offered test measures and what evidence supports using it for your concern. “Sensitivity,” “intolerance,” and “allergy” are not interchangeable promises. A colorful report ranking many foods can look decisive while failing to establish the claimed cause.

Food IgG can reflect exposure to food and may be associated with tolerance. A positive result is therefore not a sound basis for a broad elimination diet. Removing many foods without appropriate advice can make eating unnecessarily difficult and may create nutritional problems.

Choose a supervised next step

Ask the clinician whether an allergist or dietitian should be involved and what testing, if any, is justified. Oral food challenges, when appropriate, belong under medical supervision; this article does not provide a home challenge protocol.

For breathing difficulty, throat swelling, collapse, or another severe reaction, seek emergency help and follow any prescribed emergency plan. Do not wait for a purchased panel. The comparison here is about the evidence behind a testing claim, not about diagnosing an individual reaction.