Which serologic finding supports acute EBV infection in the described patient?

Which serologic finding supports acute EBV infection in the described patient?

• A. CMV IgM positive
• B. EBV IgM positive
• C. EBV IgG positive
• D. CMV IgG positive

Answer: (B)

Acute EBV infection triggers an IgM response against EBV, usually detectable as anti-viral capsid antigen (anti-VCA) IgM early in illness. This IgM appears during the acute phase and wanes as IgG rises, so its presence strongly indicates a current or very recent EBV infection. EBV IgG alone can reflect a past infection or a later stage of the current infection, but it does not confirm that the infection is acute. Finding CMV-specific antibodies (IgM or IgG) points to CMV infection, not EBV. So the best evidence for an acute EBV infection is EBV-specific IgM positivity.

Acute EBV infection triggers an IgM response against EBV, usually detectable as anti-viral capsid antigen (anti-VCA) IgM early in illness. This IgM appears during the acute phase and wanes as IgG rises, so its presence strongly indicates a current or very recent EBV infection. EBV IgG alone can reflect a past infection or a later stage of the current infection, but it does not confirm that the infection is acute. Finding CMV-specific antibodies (IgM or IgG) points to CMV infection, not EBV. So the best evidence for an acute EBV infection is EBV-specific IgM positivity.