Tissue cross reactivity assay is a standard method based on immunohistochemistry, required prior to phase I human study for therapeutic antibodies.

In drug screening, because many urine drug screens use immunoassays there is a certain amount of cross-reactivity. Certain drugs or other chemicals can give a false positive for another category of drug.

Hevein-like protein domains are a possible cause for allergen cross-reactivity between latex and banana.

Cross-reactivity may be caused by identical carbohydrate structures on unrelated proteins from the same or different species. 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. As CCDs apparently do not elicite allergic symptoms, a positive in vitro test based on IgE binding to CCDs must be rated as false positive.