Is a Mediator Release Test (MRT) valid for testing food allergies?

Mediator Release Test (MRT) Is Not Valid for Testing Food Allergies

The Mediator Release Test (MRT) should not be used for diagnosing food allergies as it lacks scientific validation and is not recommended in clinical guidelines. 1, 2

Evidence-Based Food Allergy Testing Methods

Recommended Testing Approaches

• Skin Prick Testing (SPT): The primary test for identifying IgE-mediated allergic reactions

  • More sensitive than blood testing
  • Provides direct observation of the body's reaction to specific allergens
  • Results available within 15-20 minutes 2

• Serum Allergen-Specific IgE Testing (e.g., ImmunoCAP):

  • Useful alternative when skin testing is contraindicated
  • Appropriate when patients are on medications that interfere with skin testing
  • Certain "cutoff" levels may be predictive of clinical reactivity 1, 2

• Oral Food Challenge: Gold standard for diagnosing food allergy

  • Most accurate and sensitive test
  • Presents greatest risk to the patient
  • Should be performed under medical supervision 1

Tests That Should NOT Be Used

• Mediator Release Test (MRT): Not validated for food allergy diagnosis 2
• Total Serum IgE: Should not be routinely used for food allergy diagnosis 1
• Atopy Patch Test (APT): Not recommended for routine evaluation of food allergies 1, 2
• Intradermal Testing: Should not be used to diagnose food allergies 1
• IgG-Based Testing: Not validated for food allergy diagnosis in major guidelines 2

Important Limitations of Food Allergy Testing

• Positive tests (SPT or specific IgE) indicate sensitization but not necessarily clinical allergy 1, 3
• The presence of food-specific IgE reflects allergic sensitization, not necessarily clinical reactivity 1
• Results from different laboratories or different assay systems may not be comparable 1
• Undetectable specific IgE levels can occasionally occur in patients with IgE-mediated food allergy 1

Clinical Implications

• Overreliance on laboratory testing without clinical correlation can lead to unnecessary dietary restrictions 2
• Food elimination based solely on testing without clinical symptoms may negatively impact quality of life and nutrition 2
• Unnecessary extensive testing should be avoided 2
• For non-IgE-mediated food allergies, elimination diets with careful reintroduction may be more useful than laboratory testing 1, 2

Pitfalls to Avoid

• Using unvalidated tests like MRT can lead to:

  • Misdiagnosis of food allergies
  • Unnecessary dietary restrictions
  • Potential nutritional deficiencies
  • Delayed proper diagnosis and treatment 2, 4

• Relying solely on test results without considering clinical history 1, 2

• Using broad panel allergy testing independent of clinical history 2

• Failing to refer to an allergist for proper evaluation when symptoms persist 1

The National Institute of Allergy and Infectious Diseases (NIAID) guidelines clearly state that tests like MRT have not been validated for diagnosing food allergies and should not be used in clinical practice 1. Instead, diagnosis should rely on validated methods like skin prick testing, specific IgE testing, and when necessary, oral food challenges under medical supervision.