In a 10-year-old presenting with fever, sore throat, cervical lymphadenopathy, and splenomegaly, if throat culture and Monospot test are negative, which diagnostic test is most appropriate next?

In a 10-year-old presenting with fever, sore throat, cervical lymphadenopathy, and splenomegaly, if throat culture and Monospot test are negative, which diagnostic test is most appropriate next?

• A. Chest radiograph
• B. Bone marrow examination
• C. Repeat throat culture
• D. Epstein-Barr virus titer

Answer: (D)

Infectious mononucleosis due to Epstein-Barr virus can present with fever, sore throat, cervical lymphadenopathy, and splenomegaly, and a negative throat culture plus a negative Monospot does not rule it out. The best next test is EBV-specific serology (EBV titer), which detects antibodies to viral components such as the viral capsid antigen (VCA) and EBNA. This helps determine whether an acute EBV infection is present, especially since heterophile antibodies detected by Monospot can be absent in children or early in the illness. A positive EBV titer confirms mono and guides management and counseling (including activity restrictions to protect the spleen). Chest radiograph isn’t indicated without respiratory symptoms or other indications. Repeating throat culture won’t diagnose EBV. A bone marrow examination is invasive and unnecessary for mono.

Infectious mononucleosis due to Epstein-Barr virus can present with fever, sore throat, cervical lymphadenopathy, and splenomegaly, and a negative throat culture plus a negative Monospot does not rule it out. The best next test is EBV-specific serology (EBV titer), which detects antibodies to viral components such as the viral capsid antigen (VCA) and EBNA. This helps determine whether an acute EBV infection is present, especially since heterophile antibodies detected by Monospot can be absent in children or early in the illness. A positive EBV titer confirms mono and guides management and counseling (including activity restrictions to protect the spleen).

Chest radiograph isn’t indicated without respiratory symptoms or other indications. Repeating throat culture won’t diagnose EBV. A bone marrow examination is invasive and unnecessary for mono.