Final answer:
An asymptomatic patient with greater than 20% atypical (reactive) lymphocytes on their peripheral blood smear would likely be suspected of having infectious mononucleosis, a viral infection caused by the Epstein-Barr virus (EBV).
Step-by-step explanation:
An asymptomatic patient with greater than 20% atypical (reactive) lymphocytes on their peripheral blood smear would likely be suspected of having a viral infection, specifically infectious mononucleosis. Infectious mononucleosis is caused by the Epstein-Barr virus (EBV) and is characterized by the presence of atypical lymphocytes in the blood. These atypical lymphocytes are reactive and indicate an immune response to the viral infection.