From the Guidelines
The best indicator of past Epstein-Barr virus infection is IgG anti EBNA, which corresponds to option C. This is because IgG anti-EBNA antibodies typically appear 6-12 weeks after initial infection and persist for life, making them reliable markers of previous EBV exposure 1. Some key points to consider when interpreting serological markers for EBV infection include:
- Heterophile antibodies usually become detectable between the sixth and tenth day following symptom onset, but may be false-positive in certain conditions and false-negative in approximately 10% of patients, especially children younger than 10 years 1.
- The presence of VCA IgM (with or without VCA IgG) antibodies in the absence of antibodies to EBNA indicates recent primary infection with EBV, while the presence of EBNA antibodies indicates infection more than 6 weeks from the time of the sample 1.
- IgM anti-EBNA is not a clinically useful marker, and IgG anti-early antigen (EA) may persist for months to years in some individuals but eventually becomes undetectable in most people.
- Over 90% of the normal adult population has IgG class antibodies to VCA and EBNA antigens, although approximately 5%–10% of patients who have been infected with EBV fail to develop antibodies to the EBNA antigen 1. Therefore, when determining if someone has been previously infected with EBV, testing for IgG anti-EBNA provides the most definitive evidence of past infection.
From the Research
Serological Markers for Epstein-Barr Virus Infection
The best indicator of past Epstein-Barr virus infection can be determined by analyzing the serological markers. The key markers include:
- IgG anti-VCA
- IgM anti-VCA
- IgG anti-EBNA
- Heterophile antibodies
- IgG anti-EA
Analysis of Serological Markers
Based on the studies 2, 3, 4, 5, 6, the following points can be made:
- The presence of VCA IgG and EBNA-1 IgG without VCA IgM is typical of past infection 2.
- IgG anti-EBNA is a late marker of EBV infection and indicates past infection 4, 6.
- Heterophile antibodies can be used to support the diagnosis of EBV infection, but are not specific for past infection 2, 3.
- IgM anti-VCA is an early marker of EBV infection and indicates acute infection 2, 4, 5.
- IgG anti-EA can be present in both acute and past infections, and its presence alone is not a reliable indicator of past infection 6.
Best Indicator of Past Infection
Based on the analysis, the best indicator of past Epstein-Barr virus infection is: