Food allergy can be assessed in a number of ways. Elimination diets should be followed for two to four weeks for an IgE reaction, and six weeks or so for a non-IgE reaction. However, food intake during that time needs very careful monitoring.²

Specific IgE tests can be done in vitro or using skin tests, but may not necessarily give an accurate diagnosis. Elimination diets are still required to assess the clinical relevance of the suspected allergy. Skin prick tests (SPTs) can be done at any age, but responses may be lower in infants and the elderly. Food allergy testing this way may also have low specificity or risk an extreme systemic reaction.²

Diagnostic tests that measure specific IgE antibodies have been developed for specific antigen molecules. Tests are also being developed to measure levels of basophils binding to IgE. High selectivity basophil activation tests (BATs) can be a better predictor than specific IgE or SPTs, but currently require a specialist laboratory.

However, not all tests are standardised and some tests, such as those with single recombinant protein solutions for SPTs, may lack approval for use within the EU.²