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

Short answer: there isn’t a single validated “food sensitivity” blood test that reliably identifies delayed/intolerance-type reactions for most people. The tests that are evidence-based depend on the condition you’re actually asking about (IgE allergy, celiac disease, lactose intolerance, SIBO, IBS, etc.). For general suspected food reactions the best routes are (1) assessment by an appropriate clinician and (2) diagnostic testing that is proven for the specific disorder or a structured elimination / re‑challenge done with an experienced clinician or dietitian.

What is valid and who to use

• IgE-mediated food allergy (hives, anaphylaxis, immediate reactions): see a board‑certified allergist for skin‑prick testing or serum specific‑IgE testing. The gold‑standard laboratory platform for specific IgE is ImmunoCAP (Phadia/Thermo Fisher); Quest Diagnostics and LabCorp run these tests. These tests are clinically useful when interpreted by an allergist and often followed by supervised oral food challenges when needed.
• Celiac disease: get tissue transglutaminase IgA (tTG‑IgA) and total IgA (and deamidated gliadin peptide IgG if IgA deficient). Major labs (Quest, LabCorp) perform these; a positive result is followed by gastroenterology referral and usually endoscopy/biopsy.
• Lactose/fructose malabsorption or intolerance: hydrogen breath testing (performed by GI clinics / hospital labs) is the validated test.
• SIBO (small intestinal bacterial overgrowth): validated breath tests (glucose or lactulose) through gastroenterology services.
• Eosinophilic gastrointestinal diseases: diagnosis requires endoscopy with biopsy (GI specialist).
• IBS / non‑specific food triggers: a low‑FODMAP elimination protocol supervised by a registered dietitian (RDN) is the recommended evidence‑based approach. Monash University’s low‑FODMAP resources/app are widely used in practice.

Tests to be cautious about (and why)

• IgG (food antibody) panels sold direct‑to‑consumer (Everlywell, YorkTest, many labs) or by some clinics: these measure IgG antibodies to foods. Multiple allergy/immunology and gastroenterology societies (AAAAI, EAACI, ACG, etc.) say IgG testing does not diagnose food intolerance and often just reflects exposure or tolerance rather than harmful reactions. Using IgG results to eliminate large numbers of foods can lead to unnecessary restriction and nutritional harm.
• MRT / LEAP (Oxford Biomedical): marketed for delayed reactions; some practitioners use it, but high‑quality independent evidence is limited and mainstream allergy/gastro societies do not endorse it as definitive.
• Broad “food sensitivity” arrays from direct‑to‑consumer companies: many are not supported by clinical trials showing that their recommendations reliably improve symptoms.

Practical recommendation

1. If you have immediate symptoms (anaphylaxis, hives, wheeze) — see an allergist for skin‑prick testing or ImmunoCAP serum IgE testing (Quest/LabCorp).
2. If you suspect celiac disease — order tTG‑IgA (Quest, LabCorp) before you remove gluten; follow up with GI if positive.
3. If you have bloating/diarrhea after dairy or suspected SIBO — ask GI about hydrogen breath testing.
4. If symptoms are chronic, nonspecific (bloating, fatigue, headaches, IBS‑type) — work with an experienced RDN to do a structured elimination and re‑challenge (low‑FODMAP or empiric elimination) and keep a food–symptom diary.
5. If you want a lab test, prefer validated tests run by reputable labs (ImmunoCAP for IgE; tTG for celiac; breath tests via GI clinics). Avoid paying for broad IgG panels to guide long‑term diets.

If you want, tell me your main symptoms and I’ll recommend the most appropriate validated test or clinician to see (allergist, GI, or RDN) and how to proceed.