IMMUNOLOGY

Detailed explanation-1: -The Monospot test detects heterophile antibodies produced by the immune system in response to Epstein-Barr virus (EBV) infection. These antibodies can cross-react with other types of cells, including horse red blood cells (the ones used in the monospot).

Detailed explanation-2: -The laboratory hallmark of the disease is the presence of atypical lymphocytes (a type of mononuclear cell) on the peripheral blood smear. Atypical lymphocytosis is present in approximately 75% of patients infected with mononucleosis. Greater than 10% atypical lymphocytes is diagnostic of mononucleosis.