MRT vs IgG Food Sensitivity Testing
Which Test Is Actually Accurate?

If you're researching food sensitivity testing, you've likely encountered two main options: MRT (Mediator Release Testing) and IgG antibody testing. Both claim to identify food sensitivities. Both involve a blood test. Both cost hundreds of dollars.

But they're fundamentally different tests measuring completely different things—and one has significantly better clinical validation than the other.

We'll look at the evidence objectively, including research that's critical of both approaches, so you can make an informed decision about which test—if any—is right for you.

The Short Answer

MRT vs IgG: Which Is More Accurate?

If you just want the bottom line before diving into the science:

However, this doesn't mean IgG testing is completely worthless or that MRT is perfect. Let's examine exactly what each test measures, the evidence supporting or refuting each approach, and when each might (or might not) be appropriate.

The Fundamental Difference

What Each Test Actually Measures

The most important difference between MRT and IgG testing is what they're measuring in your blood.

Analogy: IgG testing is like measuring whether you've been exposed to something (antibodies = exposure). MRT is like measuring whether that exposure causes actual inflammation (mediator release = inflammatory reaction).

Clinical Evidence

What Does the Research Say?

Research on IgG Testing

The scientific and medical community has been largely critical of IgG food sensitivity testing:

• American Academy of Allergy, Asthma & Immunology (AAAAI): States that IgG testing "should not be used as a diagnostic tool" for food sensitivities
• Canadian Society of Allergy and Clinical Immunology: Does not recommend IgG testing for diagnosing food sensitivities
• Multiple peer-reviewed studies: Show poor correlation between IgG levels and clinical food challenges (the gold standard for confirming food reactions)
• Research findings: IgG antibodies to foods are found in healthy individuals without any symptoms and often correlate with foods eaten most frequently

Key study: A 2008 study in the Journal of Allergy and Clinical Immunology found that IgG levels did not correlate with clinical food challenges and concluded that IgG testing "cannot be recommended for the diagnosis of food allergy."

References:
1. Stapel, S.O. et al. "Testing for IgG4 against foods is not recommended as a diagnostic tool: EAACI Task Force Report." Allergy, 2008 Jul;63(7):793–6. PMID: 18489614
2. Gocki, J. & Bartuzi, Z. "Role of immunoglobulin G antibodies in diagnosis of food allergy." Advances in Dermatology and Allergology, 2016 Aug;33(4):253–6. View Article

Research on MRT Testing

MRT has more limited but more positive clinical validation:

• Published accuracy data: 94.5% sensitivity and 91.7% specificity when validated against double-blind, placebo-controlled food challenges
• Clinical outcome studies: Show 75-80% of patients following MRT-guided elimination diets (LEAP Protocol) experience significant symptom improvement
• Peer-reviewed research: Studies on IBS patients following MRT-guided diets show significant symptom reduction within 10 days
• Mechanism validation: The measurement of mediator release as an indicator of food-induced inflammation has scientific basis

References:
1. Oxford Biomedical Technologies. "MRT Publications & Research." nowleap.com. View Publications
2. Mediator Release - Clinical Overview. ScienceDirect. View Articles
3. Pennington, M. "Food Sensitivity Research." meganpennington.com. View Studies

Side-by-Side

Detailed Comparison: MRT vs IgG Testing

The IgG Problem

Why IgG Testing Produces So Many False Positives

The fundamental problem with IgG testing isn't that it's measuring the wrong thing—it's that what it measures doesn't tell you what you need to know.

IgG Antibodies Are a Normal Response

When you eat food regularly, your immune system produces IgG antibodies to components of that food. This is normal and healthy. It's part of oral tolerance—your immune system learning that dietary proteins are safe.

The result? IgG tests often show "reactions" to:

• Foods you eat most frequently
• Foods that are perfectly safe for you
• Healthy foods you should continue eating

The Correlation Problem

Multiple studies show that IgG levels correlate more strongly with how often you eat a food than with whether that food causes symptoms. This makes IgG testing particularly problematic because it can:

• Flag healthy foods you eat daily (because you have antibodies from regular exposure)
• Miss foods you eat rarely but react to strongly
• Create unnecessarily restrictive diets
• Cause nutritional deficiencies from avoiding healthy foods

The MRT Advantage

Why MRT Produces More Clinically Useful Results

Learn more about how MRT testing works →

Fair Assessment

Is IgG Testing Ever Useful?

In the interest of fairness, let's acknowledge scenarios where IgG testing might have some value:

Potential Use Case: Starting Point for Elimination

Some practitioners use IgG testing as a starting point for elimination diets, fully acknowledging its limitations. The reasoning: even if results aren't perfectly accurate, they provide a structured list to try eliminating, which is better than random guessing.

The problem with this approach: You might eliminate foods you don't need to avoid while continuing to eat actual triggers, leading to frustration and abandoned protocols.

When Cost Is the Primary Barrier

IgG tests are generally cheaper than MRT ($200-$400 vs $700-800). If cost is the absolute barrier and you can't afford MRT, an IgG test might be better than nothing—but with the strong caveat that you should view results skeptically and not eliminate foods long-term without noticing symptom improvement.

The Bottom Line on IgG

IgG testing can occasionally point someone in a useful direction despite its inaccuracy, but it's not a reliable diagnostic tool. If you're going to invest in food sensitivity testing, MRT's superior accuracy and clinical validation make it the better choice for most people.

Value Assessment

Cost Comparison: Is MRT Worth the Extra Money?

MRT costs more than IgG testing. Is the extra expense justified?

Our assessment: If you're going to invest in food sensitivity testing at all, MRT's superior accuracy, professional support, and validated protocol make it worth the additional cost for most people with chronic symptoms. The cost of months spent following inaccurate IgG results—eliminating the wrong foods while continuing to eat actual triggers—often exceeds the upfront price difference.

Bottom Line

Which Test Should You Choose?

Choose MRT If:

• You want the most accurate food sensitivity test available
• You have chronic symptoms affecting multiple body systems
• You've tried elimination diets without clear success
• You suspect reactions to food chemicals (not just whole foods)
• You want professional guidance through a validated protocol
• You can afford the $400-$795 investment

Skip IgG Testing If:

• You're looking for a clinically validated, accurate test
• You don't want to risk eliminating foods unnecessarily
• You've read the research and understand the limitations

Consider Neither If:

• You can't afford any testing right now
• You're not willing to make dietary changes

Common Questions

Frequently Asked Questions

Can I do both MRT and IgG testing to be thorough?

You could, but it's generally not recommended. The tests often give contradictory results (IgG flags foods MRT shows as safe), which creates confusion rather than clarity. Since MRT has superior accuracy and clinical validation, doing both is typically a waste of money. If you're going to test, choose the more accurate option.

My naturopath recommends IgG testing. Should I trust that?

Some naturopaths and functional medicine practitioners use IgG testing despite its limitations, often because they're unaware of MRT or because the lab they work with doesn't offer it. Ask your practitioner if they're familiar with MRT and whether they're a Certified LEAP Therapist. If cost is their concern, discuss that directly rather than defaulting to a less accurate test.

I already did IgG testing. Should I redo it with MRT?

If your IgG test results helped you identify triggers and you're feeling significantly better, you may not need MRT. However, if you've been following IgG results without clear improvement, or if you're confused by the results (too many foods flagged, eliminated foods but still symptomatic), MRT testing would likely provide more accurate, actionable information.

Does MRT test for gluten sensitivity?

Yes, MRT tests your reaction to wheat and other gluten grains. However, MRT does not diagnose celiac disease (that requires specific tests and endoscopy). If you have celiac disease, you must avoid gluten completely regardless of MRT results. MRT identifies non-celiac gluten sensitivity.

How accurate is MRT for food allergy

MRT is designed to identify food sensitivities, not allergies. Food allergies are IgE-mediated and follow a different immune pathway — and because allergic reactions tend to be immediate and unmistakable, they rarely require a test to identify. That said, MRT can detect mediator release triggered by allergic reactions in the blood, though most of the immune activity in true allergies occurs at the mast cell level rather than in circulating white blood cells. If you suspect a food allergy, standard IgE allergy testing is the appropriate diagnostic tool.

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