An IgG allergy test aims to identify potential food sensitivities or intolerances by measuring certain antibodies in your blood. This type of testing has gained interest for those experiencing chronic, unexplained symptoms that might be linked to diet. Understanding these results can offer insights into how your body responds to specific foods. This guide will help you navigate the process of interpreting your IgG test results.
What IgG Testing Measures
IgG testing measures Immunoglobulin G (IgG) antibodies in the blood, which are part of your immune system’s response to foods. When your body perceives a food as a threat, it may produce IgG antibodies, leading to a food sensitivity. This often results in delayed symptoms, appearing hours or even days after consumption.
It is important to distinguish this from a true food allergy, which involves Immunoglobulin E (IgE) antibodies and typically causes immediate and sometimes severe reactions, like hives, swelling, or difficulty breathing. IgE tests (e.g., skin prick or specific IgE blood tests) diagnose these immediate, potentially life-threatening allergies. In contrast, IgG antibodies are associated with delayed hypersensitivity reactions, which are often termed food sensitivities or intolerances, and typically present with milder symptoms such as digestive issues, headaches, or fatigue.
Decoding Your Test Results
IgG test results typically present information about your body’s immune response to various foods. Reports often use numerical scales, color-coded charts, or categories like “no reactivity,” “mild,” “moderate,” or “high reactivity” to indicate IgG levels for each tested food. For example, “low reactivity” (green) might mean IgG levels between 0-9.99 µg/ml, indicating a normal response. “Moderate reactivity” (yellow) could fall between 10-19.99 µg/ml, suggesting an elevated response. “High reactivity” (red) often signifies IgG levels above 20 µg/ml, indicating a strong immune response.
Elevated IgG levels suggest your immune system has reacted to a food. This can happen if the food is consumed regularly, or if there is compromised gut integrity, allowing food particles to enter the bloodstream and trigger an immune response. While higher scores can indicate an abnormal response, exact numerical thresholds for “normal” versus “elevated” vary between laboratories. Some labs consider IgG antibody levels above 30 U/mL elevated, while others use different scales.
Next Steps After Testing
After receiving IgG test results, an elimination diet is often the next step. This involves temporarily removing foods identified with higher IgG reactivity from your diet for a set period, typically four weeks. The purpose is to allow your digestive system to “reset” and reduce any potential immune response. Foods with moderate or high reactivity are prioritized for elimination; those with minimal or low reactivity are less likely to cause issues.
During the elimination phase, it is helpful to keep a detailed food diary. This record should include everything you eat and drink, along with the time of consumption and any symptoms experienced, noting intensity and duration. This meticulous tracking helps in identifying patterns and correlations between specific foods and your body’s reactions. After the elimination period, foods are systematically reintroduced, one at a time, for several days while continuing to monitor symptoms in your food diary.
Consulting a healthcare professional (e.g., doctor or registered dietitian) is important for personalized guidance throughout this process. They can help interpret your results in the context of your overall health, symptoms, and medical history, and assist in designing a balanced elimination and reintroduction plan. This professional support helps ensure you maintain adequate nutrition and accurately identify your body’s responses to specific foods.
Important Considerations About IgG Tests
Approach IgG testing understanding its place within the broader scientific community. Major allergy organizations (e.g., American Academy of Allergy, Asthma & Immunology (AAAAI), European Academy of Allergy and Clinical Immunology (EAACI), and Canadian Society of Allergy and Clinical Immunology (CSACI)) do not widely endorse IgG testing as a diagnostic tool for food allergies or sensitivities. They state that the presence of IgG antibodies often reflects exposure to a food, and potentially tolerance, rather than an allergy or intolerance.
Therefore, IgG test results should not be used in isolation to diagnose true food allergies, which are typically identified through IgE testing, medical history, and physical examination. Unnecessary dietary restrictions based solely on IgG results could lead to nutritional deficiencies or decreased quality of life. While some individuals report symptom improvement after following an IgG-guided elimination diet, these tests are best viewed as one piece of information to consider alongside personal symptoms and professional guidance.