If Monospot test is negative in a presentation suggestive of infectious mononucleosis, which test would most reliably confirm EBV infection?

If Monospot test is negative in a presentation suggestive of infectious mononucleosis, which test would most reliably confirm EBV infection?

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

Answer: (A)

When mononucleosis is suspected but the Monospot (heterophile antibody) test is negative, the most reliable way to confirm EBV infection is through EBV-specific serology. This means testing for antibodies against EBV antigens, particularly VCA IgM and VCA IgG, and EBNA IgG. The pattern helps distinguish acute infection (VCA IgM present, VCA IgG rising) from past infection (EBNA IgG positive with waning VCA IgM). Monospot can be negative early in illness or in some patients, so EBV-specific antibodies provide a more accurate confirmation. The other options aren’t appropriate for confirming EBV infection. A throat culture looks for bacterial causes like group A Streptococcus. A chest radiograph isn’t diagnostic for EBV. A bone marrow examination is invasive and not used to diagnose EBV mononucleosis.

When mononucleosis is suspected but the Monospot (heterophile antibody) test is negative, the most reliable way to confirm EBV infection is through EBV-specific serology. This means testing for antibodies against EBV antigens, particularly VCA IgM and VCA IgG, and EBNA IgG. The pattern helps distinguish acute infection (VCA IgM present, VCA IgG rising) from past infection (EBNA IgG positive with waning VCA IgM). Monospot can be negative early in illness or in some patients, so EBV-specific antibodies provide a more accurate confirmation.

The other options aren’t appropriate for confirming EBV infection. A throat culture looks for bacterial causes like group A Streptococcus. A chest radiograph isn’t diagnostic for EBV. A bone marrow examination is invasive and not used to diagnose EBV mononucleosis.