In infectious mononucleosis what does the monospot test detect

In infectious mononucleosis the monospot test detects heterophil antibodies. The mononuclear spot test or monospot test is a form of the heterophile antibody test for a rapid detection of infectious mononucleosis due to Epstein–Barr virus (EBV). The test is specific for heterophile antibodies produced by the human immune system in response to EBV infection. About 70%–80% of patients with infectious mononucleosis produce these heterophile antibodies, which are not specific for EBV infection but are good predictors.

In infectious mononucleosis (IM), the monospot test detect the IgM. Infectious mononucleosis is also called the kissing disease. It is caused by the virus Epstein-Barr virus, however other virus may cause the disease. IgM is present on the B cells and mainly functions in the control of B-cell activation. 

Ithink the answer is nuclear membrane