Cross-reactivity is also a commonly evaluated parameter for the validation of immune and protein binding based assays such as ELISA and RIA.
In this case it is normally quantified by comparing the assay's response to a range of similar analytes and expressed as a percentage.
Tissue cross-reactivity assay is a standard method based on immunohistochemistry, required prior to phase I human studies for therapeutic antibodies.
However, many naturally occurring apparent antigens are actually a mixture of macromolecules (for example, from pathogens, toxins, proteins, or pollen) comprising several epitopes.
There may even be cross reactivity between two non-pathogens;[5] for example, Hevein-like protein domains are a possible cause for allergen cross-reactivity between latex and banana.
Such cross-reactive carbohydrate determinants (CCDs) are an issue in allergy diagnosis, where about a fifth of all patients displays IgE antibodies against Asn-linked oligosaccharides (N-glycans) containing core α1,3-linked fucose.