Can an allergy blood test come back with a false positive?
The easy answer to you question is “yes.” Just like any other test, there can be false outcomes. The accuracy depends on if it was a RAST or ImmunoCAP test. The test can come back with anti-gluten-like antigens, which bind with the anti-gluten IgE on the test panel and give a positive result. Allergies are person-specific. Just because you have the antibodies in your blood, that doesn’t mean that physical symptoms are immediate or like other people’s symptoms. Sometimes the allergies can be as subtle as being slightly more tired or a little more water in the stool. Also, the antibody class switching from IgM to IgE could be recent and the response still fairly low due to lack of antigen-specific sentinel cells in the lumen. What is positive today may be negative next month. Not every positive test results in a measurable response. The antibodies may fade over time as the body realizes that gluten and casein are not a threat.
