The term "heterophil test" refers to a laboratory test used to detect the presence of infectious mononucleosis, a viral illness that typically affects young adults. There are several synonyms for this term, including the monospot test, the Paul-Bunnell test, and the Epstein-Barr virus antibody test. Each of these tests uses different methodologies to detect the presence of antibodies produced in response to the virus, but they are all designed to identify the same underlying illness. Other less commonly used synonyms for the heterophil test may include the Forssman antibody test and the VCA-IgM antibody test, both of which may be used to detect presence of the Epstein-Barr virus.