Verbatim response from ChatGPT
Short answer: there isn’t a single reliable, clinically validated “food sensitivity” blood test sold direct-to-consumer. Many commercial IgG-based panels (Everlywell, Vibrant, Cyrex, ALCAT, some MRT offers) measure IgG or other markers that indicate exposure, not clinically meaningful intolerance, and are not recommended by allergy societies. The safest, evidence-based approach is to use standard allergy and intolerance testing or a medically supervised elimination/rechallenge.
What to use instead (by situation)
- Suspect true allergy (immediate, hives, breathing, anaphylaxis): see an allergist for skin-prick testing or serum specific IgE testing (ImmunoCAP/Phadia assays). Reputable labs that run these assays include Quest Diagnostics, LabCorp and Mayo Clinic Laboratories. These tests detect IgE-mediated allergy and are clinically validated.
- Suspect celiac disease (bloating, diarrhea, weight loss, iron deficiency): get celiac serology — tissue transglutaminase IgA (tTG‑IgA) plus total IgA (and deamidated gliadin peptides if needed). Available at Quest, LabCorp, Mayo Clinic Labs.
- Suspect carbohydrate intolerance (lactose/fructose) or SIBO: breath testing (hydrogen/methane) performed by gastroenterology clinics or diagnostic labs (many GI offices, Genova Diagnostics provide kits). These tests are the accepted method for lactose/fructose intolerance and SIBO diagnosis.
- Non-IgE, delayed or vague symptoms (IBS-like, fatigue, headaches): the best validated approach is a structured elimination diet with careful reintroduction (gold standard: double-blind, placebo-controlled food challenge when needed). Work with a board-certified allergist or a registered dietitian (RD) experienced in food elimination/rechallenge.
Why not IgG panels sold direct-to-consumer?
- IgG antibodies often reflect prior exposure and tolerance, not harmful reaction. Major allergy/immunology organizations (e.g., AAAAI) advise against using IgG testing for diagnosing food intolerance or guiding elimination diets.
- These tests can lead to unnecessary, restrictive diets that cause nutritional problems and anxiety.
If you want a reputable starting point
- Make an appointment with a board-certified allergist for history and either skin-prick testing or serum specific IgE (ImmunoCAP via Quest/LabCorp/Mayo).
- For GI-type symptoms, ask your primary care provider or gastroenterologist about breath testing (lactose/fructose/SIBO) and celiac serology.
- If you choose an elimination diet, consult a registered dietitian (look for RD who specializes in GI/allergy).
If you tell me your main symptoms (hives/anaphylaxis, chronic GI symptoms, headaches, eczema, etc.) I can recommend the single best next test or specialist to see.