What is the best food sensitivity test that is not a scam?

Short answer: there is no single, reliable “food sensitivity” blood test that proves which foods are causing non‑allergic symptoms. Many popular direct‑to‑consumer IgG food‑testing kits are not recommended by allergy and gastroenterology societies and can be misleading. The “best” test depends on what you suspect (true allergy, celiac disease, lactose/fructose intolerance, IBS/FODMAPs, etc.). Below are evidence‑based options and specific brands/services to use.

What to avoid

• IgG/IgG4 panels sold direct‑to‑consumer (Everlywell Food Sensitivity, YorkTest, Vibrant, many others). Major bodies (AAAAI, BSACI and others) say IgG reflects exposure, not harmful sensitivity, and should not be used to diagnose food intolerance.

Legitimate tests to consider (by suspected problem)

1. Suspected immediate (allergic) reaction — hives, swelling, anaphylaxis, or rapid symptoms

• Best: evaluation by a board‑certified allergist with skin‑prick testing and/or serum specific IgE testing.
• Specific test/brand: ImmunoCAP specific IgE (Thermo Fisher) — commonly run by major labs (Quest Diagnostics, Labcorp) and used clinically worldwide. Skin testing is done in clinic (faster and often more sensitive for IgE‑mediated allergy).

1. Suspected celiac disease (diarrhea, weight loss, iron deficiency, family history)

• Best: tissue transglutaminase IgA (tTG‑IgA) plus total IgA; if IgA deficient, deamidated gliadin peptide (DGP) IgG.
• Available from mainstream labs (Quest, Labcorp). Important: keep eating gluten until tested.

1. Suspected lactose or carbohydrate malabsorption

• Best: hydrogen breath test for lactose/fructose/other carbohydrate malabsorption.
• Commonly done in GI clinics; equipment/brands include QuinTron breath analyzers used by many centers. Sensible, evidence‑based test.

1. Suspected SIBO or gas‑related symptoms

• Best: lactulose (or glucose) hydrogen/methane breath testing — available through GI clinics and specialized labs (again, QuinTron is widely used).

1. Non‑IgE, non‑celiac symptoms (IBS‑type symptoms, “food sensitivity” without allergy)

• Best: an elimination diet with structured reintroduction under guidance of a registered dietitian (RDN). For IBS, a low‑FODMAP diet trial supervised by an RDN trained in Monash University FODMAP methods is the evidence‑based approach (Monash University provides research and apps used by clinicians).
• There is no validated single blood test for non‑celiac gluten sensitivity or histamine intolerance; trial and re‑challenge is the reliable method. DAO (diamine oxidase) tests exist but have limited and inconsistent evidence.

Other tests to be cautious about

• ALCAT, MRT (Mediator Release Test), various cytotoxic tests, and many proprietary panels that claim to find “food sensitivities” — evidence is weak/absent and they often lead to unnecessary, restrictive diets.

Practical next steps

• If you have immediate allergic symptoms (hives, swelling, throat tightness, fainting), see an allergist now.
• If GI symptoms are dominant (bloating, diarrhea, gas), start with your primary care provider or a gastroenterologist for appropriate testing (celiac panel, breath test) and get referred to a dietitian for structured elimination/rechallenge.
• If you want testing for true food allergy, book an appointment with an allergist who can do skin testing and/or ImmunoCAP specific IgE testing (Quest/Labcorp use ImmunoCAP in many labs).

If you tell me the symptoms you’re worried about (timing of reactions, GI vs skin vs respiratory, how quickly symptoms start), I can say which specific test or specialist is most appropriate and help you find a local lab/clinic.