What does a reactive Epstein-Barr Virus (EBV) Capsid Immunoglobulin G (IgG) and nuclear Antibody (Ab) IgG result indicate?

Interpreting Reactive EBV Capsid IgG + Nuclear Ab IgG Results

The presence of both reactive Epstein-Barr Virus (EBV) Capsid IgG and Nuclear Antibody (EBNA) IgG indicates past EBV infection that occurred more than 6 weeks ago and is not likely the cause of current symptoms. 1

Antibody Pattern Interpretation

The EBV antibody pattern showing:

• Positive VCA IgG (Viral Capsid Antigen IgG)
• Positive EBNA IgG (Epstein-Barr Nuclear Antigen IgG)

This specific pattern has a clear interpretation in EBV serology:

• Past infection: When both VCA IgG and EBNA IgG are present, this indicates the person had an EBV infection that occurred at least 6-8 weeks ago 1
• Lifelong persistence: These antibodies typically remain detectable for life after primary infection 1
• Common finding: Over 90% of the normal adult population has IgG class antibodies to both VCA and EBNA antigens 1

Clinical Significance

This antibody pattern has several important clinical implications:

1. Not acute infection: The presence of EBNA antibodies rules out recent primary infection as these antibodies develop one to two months after primary infection 1

2. Latent infection: EBV establishes lifelong latent infection after primary infection, with over 90% of adults worldwide being EBV-seropositive

3. Current symptoms: If the patient has current symptoms, they are likely not due to acute EBV infection and other causes should be investigated 1

4. Reactivation possibility: While this pattern typically indicates past infection, it's worth noting that in some cases, EBV can reactivate. However, reactivation is generally diagnosed through additional testing such as viral load or IgM antibodies, not just by the presence of IgG antibodies 1

Additional Testing Considerations

If there are clinical concerns about active EBV infection despite this serological pattern:

• VCA IgM: Testing for VCA IgM would help identify recent infection (though not included in the current results) 1
• EBV viral load: In cases where reactivation is suspected, especially in immunocompromised patients, quantitative EBV DNA testing may be useful 1
• Heterophile antibodies: These are typically present in acute infection but absent in past infection 2

Common Pitfalls to Avoid

• Misinterpreting as acute infection: The presence of both VCA IgG and EBNA IgG should not be interpreted as evidence of acute infection
• Attributing symptoms to EBV: With this antibody pattern, current symptoms are likely due to other causes
• Missing immunocompromised status: In immunocompromised patients, this pattern may still be associated with EBV reactivation, which would require additional testing 1
• Ignoring the 5-10% exception: Approximately 5-10% of patients who have been infected with EBV fail to develop antibodies to the EBNA antigen, which can complicate interpretation 1

This serological pattern is one of the most common and straightforward to interpret in EBV testing, representing past infection in an immunocompetent individual.