What is Immunoglobulin G (IgG) food sensitivity testing?

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Last updated: May 5, 2025 • View editorial policy

From the Guidelines

IgG food sensitivity testing is not recommended for diagnosing food allergies or intolerances due to its lack of scientific validity and potential to lead to unnecessary dietary restrictions. The presence of IgG antibodies to foods is a normal immune response to food exposure, not necessarily an indication of adverse reactions 1. Instead, if food sensitivities are suspected, an elimination diet under healthcare supervision is a more effective approach, where suspected trigger foods are removed for 2-4 weeks and then reintroduced systematically while monitoring symptoms.

Some of the key issues with IgG food sensitivity testing include:

  • Poor specificity and applicability of IgG antibody testing, with IgG antibodies to yeast reported in 87% of patients yet rarely responsible for symptoms following dietary rechallenges 1
  • Lack of correlation between IgG antibodies and actual food intolerances, with many individuals having IgG antibodies to foods without experiencing adverse reactions
  • Potential for unnecessary dietary restrictions, which can lead to nutritional deficiencies and anxiety around eating

In contrast, validated tests for true food allergies include skin prick tests and IgE blood tests performed by allergists 2. The British Society of Gastroenterology guidelines on the management of irritable bowel syndrome also recommend against using IgG food sensitivity testing, instead suggesting traditional dietary advice, a low FODMAP diet, or a gluten-free diet as potential treatment options 1.

Key considerations for healthcare providers include:

  • Carefully evaluating the potential benefits and harms of IgG food sensitivity testing
  • Considering alternative diagnostic approaches, such as elimination diets, to identify food sensitivities
  • Providing patients with accurate information about the limitations and potential risks of IgG food sensitivity testing.

From the Research

IgG Food Sensitivity Testing

  • IgG food sensitivity testing has been studied as a potential diagnostic tool for various conditions, including migraine headaches and irritable bowel syndrome (IBS) 3, 4, 5, 6.
  • The test measures the levels of immunoglobulin G (IgG) antibodies against specific foods, which can indicate an immune response to those foods 7.
  • Some studies have found that eliminating foods based on IgG antibody tests can lead to significant reductions in symptoms for patients with migraine headaches and IBS 3, 4.
  • However, other studies have questioned the validity of IgG food sensitivity testing as a diagnostic tool, citing a lack of convincing evidence for its effectiveness 7.
  • The presence of IgG antibodies against foods may indicate immunological tolerance rather than hypersensitivity, and testing for IgG4 against foods is not recommended as a diagnostic tool 7.

Clinical Applications

  • IgG food sensitivity testing may be used to create customizable dietary recommendations for patients with migraine headaches and IBS 6.
  • Some healthcare practitioners believe that IgG food sensitivity testing can be a beneficial tool for identifying food sensitivities and intolerances, particularly for patients who experience delayed symptoms 6.
  • However, more research is needed to fully understand the relationship between IgG food sensitivities and various symptoms and disorders 6.

Study Findings

  • A 2013 study found that an IgG-based elimination diet significantly reduced symptoms in patients with migraine headaches and IBS 3.
  • A 2007 study found that eliminating allergic foods based on IgG antibody tests improved symptoms and quality of life in patients with IBS 4.
  • A 2005 study found that IBS patients had significantly higher IgG4 titers to certain foods, including wheat, beef, and pork, compared to controls 5.
  • A 2008 study found that testing for IgG4 against foods is not recommended as a diagnostic tool due to a lack of convincing evidence for its effectiveness 7.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.