From the Guidelines
The patient should eliminate banana, beef, and corn from their diet for 3-6 months due to high sensitivity levels, as indicated by the RAST test results showing values above the high normal range. This recommendation is based on the guidelines for the diagnosis and management of food allergy, which suggest that while RAST tests have a low positive predictive value for clinical diagnosis, they can still identify foods potentially provoking IgE-mediated food-induced allergic reactions 1.
Interpretation of RAST Results
- Banana (RAST) IgG: 7.3, which is above the high normal range, indicating a potential sensitivity.
- Beef (RAST) IgG: 10.8, significantly above the high normal range, suggesting a high sensitivity.
- Corn (RAST) IgG: 3.6, above the high normal range, indicating a potential sensitivity.
- Other foods like chicken, soybean, and rice showed no significant sensitivity, with values below the high normal range.
Recommended Course of Action
- Eliminate highly sensitive foods (banana, beef, and corn) for 3-6 months to assess symptom improvement.
- Maintain a detailed food diary to track symptoms after reintroduction of these foods.
- Consider nutritional counseling to ensure dietary adequacy during the elimination phase.
- After the elimination period, reintroduce foods one at a time, with 2-3 days between each new food, to clearly identify triggers.
- Have an emergency action plan in place, and consider carrying an epinephrine auto-injector if severe reactions have occurred previously, as recommended by guidelines for managing food allergies 1.
From the Research
Interpretation of RAST Results
- The patient's RAST results show elevated IgG levels for certain foods, including banana (7.3), beef (10.8), and corn (3.6), indicating potential food sensitivities 2.
- The results also show normal IgG levels for chicken (<2.0), soybean (<2.0), and other foods, suggesting no sensitivities to these foods.
- However, some foods, such as peanut, tomato, tuna, sweet potato, rye, brewer's yeast, and rice, have "QNS" (quantity not sufficient) results, which may indicate insufficient sample quantity or other technical issues.
Recommended Course of Action
- Based on the study by 2, elimination of the positive foods (banana, beef, and corn) may be recommended as a treatment approach, as it demonstrated a 71% success rate in achieving at least 75% improvement in symptoms.
- However, it is essential to consider the limitations of IgG testing, as highlighted by 3, which suggests that IgG4 testing is not a reliable diagnostic tool for food hypersensitivity and may indicate immunological tolerance rather than hypersensitivity.
- A more comprehensive approach, including clinical evaluation and oral food challenges, may be necessary to confirm food sensitivities and develop an effective treatment plan, as recommended by 4 and 5.
- The patient's symptoms and medical history should be carefully evaluated, and a healthcare professional should be consulted to determine the best course of action.