How do you get a positive skin allergy test and negative blood test. I had food tests came back level 4 allergic for several foods then the negative.?

Possible explanations for a positive skin allergy test and a negative blood test:

1. Recent allergen exposure: If you were recently exposed to the allergen before the blood test, it's possible that the allergen-specific antibodies (IgE antibodies) had not yet reached detectable levels in your blood. Skin tests detect IgE antibodies bound to mast cells in the skin, which can be more sensitive than blood tests in some cases.

2. Type of allergen: Some allergens may be more likely to cause a positive skin test than a positive blood test. For example, inhalant allergens (such as pollen or dust mites) tend to elicit stronger skin test responses compared to food allergens.

3. Individual immune response: Individual variations in immune responses can affect the results of allergy tests. Some people may produce more IgE antibodies in response to certain allergens, leading to a positive skin test, while their blood test results remain negative.

4. Technical factors: Blood tests for allergies have a lower sensitivity compared to skin tests, meaning they may be less likely to detect certain allergies. Additionally, the timing of the blood draw, test methodology, and laboratory variations can influence the results.

5. Cross-reactivity: If you have an allergy to one substance (e.g., a certain type of pollen), you may also have a positive skin test to related substances (e.g., other types of pollen or fruits) due to cross-reactivity. However, this doesn't necessarily mean you're allergic to all the substances that show positive skin test reactions.

It's important to consult with an allergist or immunologist to interpret your allergy test results accurately. They can consider your symptoms, medical history, and the specific results of both the skin test and the blood test to make an informed diagnosis and recommend appropriate management strategies.