Does a positive IgG result mean I am allergic to that food?

No. Elevated IgG indicates immune recognition and exposure but is also found in healthy individuals who tolerate the food. A positive result suggests that food as a candidate for elimination–rechallenge; only symptom improvement during elimination and recurrence on rechallenge confirm clinical intolerance.

Why do major allergy societies not recommend IgG food testing?

Organisations such as EAACI and the Canadian Society of Allergy and Clinical Immunology state that IgG to food is a normal immune response to dietary exposure and does not diagnose food intolerance. The test is used within functional medicine as a screening tool, with the understanding that results must be validated by clinical trials.

How long should I eliminate a food if it shows high IgG?

Practitioners typically recommend a strict elimination for 4–6 weeks to allow symptoms to resolve and antibody titres to decline, followed by supervised rechallenge. The rechallenge is the definitive step to establish clinical relevance.

Can I test while on an elimination diet?

Testing during elimination may yield false-negative results because IgG titres decline without antigen exposure. Patients should be consuming the foods of interest for at least two weeks before sample collection to ensure accurate results.

Is the dried blood spot as accurate as a venous draw?

Dried blood spot sampling is validated for IgG quantitation and offers the convenience of at-home collection. Proper technique — fully saturating each circle and air-drying the card — is essential; poorly collected spots can yield unreliable results.

Will this test diagnose coeliac disease?

No. Coeliac disease requires specific serology (tissue transglutaminase IgA, endomysial IgA) and, if positive, duodenal biopsy. The IgG panel may show elevated IgG to gluten but does not replace coeliac-specific testing.

How many foods should I eliminate based on the results?

Eliminating too many foods risks nutritional deficiency and is often impractical. Most practitioners prioritise the highest-reactive foods (typically ≥200–400 U/mL) and eliminate those in a structured trial, adding back one food at a time during rechallenge to identify true triggers.

BML-FSA-008food sensitivity allergyUSA

144 Food Panel: IgG

Q: What is the difference between IgG and IgE food testing?

IgE antibodies mediate immediate allergic reactions such as anaphylaxis and hives, tested by standard allergy serology or skin prick. IgG antibodies are proposed to reflect delayed or non-IgE-mediated food sensitivities and are used to investigate chronic symptoms not explained by IgE testing. The two address different immune mechanisms.

The 144 Food Panel: IgG test quantifies IgG antibodies to 144 dietary antigens from a dried blood spot, used in functional medicine to investigate suspected delayed food reactions. Elevated IgG indicates immune recognition and guides elimination–rechallenge trials; the test is a hypothesis-generating tool, not a diagnostic standard, and results must be correlated with clinical response.

Biomarkers

Dried blood spot

Sample

7–10 business days

Turnaround

Fasting

What is the 144 Food IgG test?

The 144 Food Panel: IgG test quantifies IgG antibodies to a broad array of dietary antigens using dried blood spot sampling. It is positioned within functional and integrative medicine as a screening tool for food sensitivities that may manifest as delayed, non-IgE-mediated symptoms — bloating, fatigue, headache, joint pain, or chronic inflammation — which do not appear on standard IgE skin-prick or specific-IgE serology. Practitioners order this panel when a patient's history suggests food-triggered symptoms but conventional allergy testing is unrevealing. The evidence base for food-specific IgG testing is debated: several major allergy societies caution that IgG to food is a marker of exposure and tolerance rather than intolerance, yet clinical experience and selected studies report symptom improvement following IgG-guided elimination diets. The test is best understood as a functional tool to prioritise foods for supervised elimination–rechallenge rather than a definitive diagnostic for food intolerance, and results must be correlated with the patient's symptom diary and clinical response.

What does the 144 Food IgG test measure?

IgG(Food-Specific Immunoglobulin G)

Range: Negative <100 U/mL; borderline 100–200 U/mL; moderate 200–400 U/mL; high ≥400 U/mL (platform-specific thresholds).Optimal: The concept of 'optimal' IgG is method-dependent and not well defined; the clinical utility lies in the pattern and magnitude of reactivity relative to symptoms, not in achieving a target antibody level.U/mL / arbitrary units

Food-specific IgG antibodies are generated following exposure to dietary proteins. IgG is the most abundant immunoglobulin class in serum and can reflect both immune tolerance and sensitisation. Unlike IgE-mediated immediate hypersensitivity, IgG antibodies form immune complexes that may activate complement and engage Fc receptors, and elevated titres to specific foods are proposed by some practitioners to correlate with delayed or non-IgE symptoms, though this interpretation remains contested within conventional allergy and immunology.

Food-specific IgG testing is ordered by practitioners investigating suspected delayed or non-IgE-mediated food reactions in patients with chronic gastrointestinal symptoms, inflammatory conditions, or systemic complaints not explained by standard IgE allergy testing. Elevated IgG to a food indicates exposure and immune recognition but does not establish causation of symptoms; many healthy individuals mount IgG responses to commonly eaten foods as part of normal mucosal immunity. The test is used as a hypothesis-generating tool to guide elimination–rechallenge trials rather than as a stand-alone diagnostic.

Why is the 144 Food IgG test ordered?

Patients with chronic gastrointestinal symptoms — bloating, diarrhoea, abdominal pain — in whom coeliac disease, inflammatory bowel disease, and IgE allergy have been excluded
Investigation of suspected delayed food reactions in individuals with migraine, chronic fatigue, or fibromyalgia where dietary triggers are suspected
Assessment of food sensitivities in autoimmune or inflammatory conditions (rheumatoid arthritis, eczema, psoriasis) where empiric elimination has been considered
Patients seeking personalised dietary guidance after standard dietary trials (low-FODMAP, gluten-free) have yielded incomplete or inconsistent results
Exploration of food reactivity in paediatric populations with behavioural or developmental concerns where a dietary influence is suspected, though caution is warranted given the contested evidence base
Athletes or individuals with chronic low-grade inflammation investigating whether dietary antigens contribute to performance or recovery issues

Sample collection and turnaround

Sample type

Dried blood spot

Fasting required

Collection method

Finger prick

Turnaround

7–10 business days

Collection notes

Patient self-collection using the kit provided by US BioTek. The finger is cleansed, pricked with a sterile lancet, and the blood spot card is saturated with capillary blood. All circles on the card must be completely filled; partially filled or layered spots may yield unreliable results. The card is air-dried, packaged, and returned by post. Patients should be consuming a varied diet including the foods of interest for at least two weeks before collection to ensure adequate antigen exposure.

Specimen requirements

Fully saturated dried blood spot card, air-dried for at least two hours, returned in the prepaid envelope. Avoid contact with contaminants or moisture during drying and transit. Note date and time of collection.

What can affect 144 Food IgG results?

reducesRecent food avoidance or elimination diet

IgG antibody titres wane following several weeks of food avoidance, so a current elimination diet may yield false-negative results; patients should be consuming a varied diet before testing.

reducesImmunosuppressive or immunomodulatory therapy

Corticosteroids, biologics, and other immunosuppressants can blunt antibody responses, potentially lowering food-specific IgG titres and reducing test sensitivity.

variableRecent infection or vaccination

Acute immune activation can transiently shift antibody production, though the effect on food-specific IgG is usually minimal; timing around major illness or vaccination is worth noting.

elevatesGut permeability and mucosal inflammation

Increased intestinal permeability may permit greater antigen translocation and drive higher IgG responses, so elevated titres may reflect gut barrier dysfunction as much as true intolerance.

variableSample quality and spot saturation

Dried blood spot collection requires adequate saturation; insufficient or unevenly saturated spots can yield unreliable quantitation, so adherence to collection instructions is critical.

variableCross-reactivity among homologous proteins

IgG antibodies may cross-react with structurally similar proteins (e.g. different legumes, tree nuts), so a positive result to one food may not mean all related foods must be eliminated; clinical correlation is essential.

What do 144 Food IgG results mean?

Elevated

Moderate or high IgG titres (typically ≥200 U/mL) suggest immune recognition and potential sensitisation to that food. Common highly reactive foods include dairy, gluten-containing grains, eggs, soy, and certain nuts. Elevated IgG does not prove the food causes symptoms — it indicates a candidate for elimination. Practitioners typically recommend a structured elimination (4–6 weeks) of high-reactive foods followed by supervised rechallenge to assess symptom response, which is the gold standard for confirming clinical relevance.

Normal

Borderline or low-normal IgG across the panel suggests either genuine tolerance, recent elimination, or that non-IgG mechanisms (IgE, cell-mediated, or non-immune mechanisms such as enzyme deficiencies or fermentation) underlie the patient's symptoms. A negative IgG panel does not exclude food intolerance.

Reduced

Low or negative IgG to a food suggests minimal immune exposure or tolerance and is not typically actionable. However, if the patient has been avoiding that food, low IgG may reflect avoidance rather than true non-reactivity.

Note: IgG to food is present in healthy individuals and correlates with dietary exposure. The test is a functional, hypothesis-generating tool, not a diagnostic gold standard; clinical decisions must incorporate symptom diaries, elimination–rechallenge outcomes, and the full clinical context. Over-interpretation can lead to unnecessarily restrictive diets and nutritional deficiencies, so results should guide supervised trials rather than blanket avoidance. Major allergy societies do not endorse IgG testing for routine diagnosis of food allergy or intolerance.

Frequently asked questions

IgE antibodies mediate immediate allergic reactions such as anaphylaxis and hives, tested by standard allergy serology or skin prick. IgG antibodies are proposed to reflect delayed or non-IgE-mediated food sensitivities and are used to investigate chronic symptoms not explained by IgE testing. The two address different immune mechanisms.

How to access the 144 Food IgG test

The 144 Food IgG reference page is free and open to all practitioners. Create a free practitioner account to see pricing, save tests to your list, and generate requisition forms. Verification takes 1–2 business days.

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About this page

Published: October 7, 2026

Last reviewed: October 7, 2026

References:

Stapel SO, et al. Testing for IgG4 against foods is not recommended as a diagnostic tool: EAACI Task Force Report. Allergy. (2008)
Carr S, et al. CSACI position statement on the testing of food-specific IgG. Allergy Asthma Clin Immunol. (2012)
Atkinson W, et al. Food elimination based on IgG antibodies in irritable bowel syndrome: a randomised controlled trial. Gut. (2004)
Zuo XL, et al. Alterations of food antigen-specific serum immunoglobulins G and E antibodies in patients with irritable bowel syndrome and functional dyspepsia. Clin Exp Allergy. (2007)

This content is for licensed healthcare practitioners only and does not constitute medical advice. Clinical decisions should be based on the full clinical picture and not on any single test result.