From the Guidelines
These lab results indicate a past Epstein-Barr virus (EBV) infection that is not currently active, as evidenced by the negative EBV VCA IgM antibody (<36.0 U/mL) and highly positive EBV VCA IgG and EBV Nuclear Antigen IgG antibodies (>600.0 U/mL) 1. The presence of VCA IgM antibodies is typically associated with recent primary infection, but in this case, the negative result suggests that the infection is not recent 1. The high levels of EBV VCA IgG and EBV Nuclear Antigen IgG antibodies indicate long-term immunity to EBV, which is consistent with normal immunity developed by most adults over their lifetime 1. It is essential to note that the high antibody levels do not indicate any current illness and are simply a marker of the immune system's previous encounter with the virus. No specific treatment is needed for past EBV infections, as the virus remains dormant in most people without causing problems. The pattern of negative EBV VCA IgM and positive EBV VCA IgG and EBV Nuclear Antigen IgG antibodies is common in individuals who had mononucleosis ("mono") or an asymptomatic EBV infection months to years ago 1. In clinical practice, the diagnosis of EBV infection is often guided by the presence of clinical symptoms, such as fever, sore throat, and lymphadenopathy, in addition to laboratory test results 1. The laboratory diagnosis of EBV infection may involve additional tests, such as heterophile antibody tests or NAAT, to confirm the diagnosis and rule out other causes of mononucleosis-like illnesses 1. However, in this case, the lab results provide sufficient evidence to indicate a past EBV infection that is not currently active. Key points to consider in the interpretation of these lab results include:
- The negative EBV VCA IgM antibody result indicates no recent or acute infection
- The highly positive EBV VCA IgG and EBV Nuclear Antigen IgG antibodies indicate long-term immunity to EBV
- The high antibody levels do not indicate any current illness
- No specific treatment is needed for past EBV infections.
From the Research
Interpretation of EBV Serological Results
The provided serological results for EBV antibodies can be interpreted based on the reference ranges and units provided.
- EBV Ab VCA, IgM: <36.0 U/mL is considered negative, 36.0 - 43.9 U/mL is equivocal, and >43.9 U/mL is positive 2, 3.
- EBV Ab VCA, IgG: <18.0 U/mL is considered negative, 18.0 - 21.9 U/mL is equivocal, and >21.9 U/mL is positive 2, 3.
- EBV Nuclear Antigen Ab, IgG: <18.0 U/mL is considered negative, 18.0 - 21.9 U/mL is equivocal, and >21.9 U/mL is positive 2, 3.
Diagnostic Approaches
To distinguish between acute and past EBV infection, the presence of VCA IgM and VCA IgG without EBNA-1 IgG indicates acute infection, whereas the presence of VCA IgG and EBNA-1 IgG without VCA IgM is typical of past infection 2.
- The use of IgG avidity measurement can aid in the diagnosis of primary EBV infection, as low-avidity IgG anti-VCA is typically seen in recent infection 3.
- A study evaluating the Architect EBV antibody panel demonstrated high sensitivity and specificity for diagnosing primary, past, and absent EBV infection 4.
Serological Patterns
The interpretation of EBV serological patterns can be challenging due to the various possible combinations of antibodies 5.
- A study utilizing a large population of patients developed evidence-based tools for interpreting EBV results, including easy-to-use tables for interpreting serological patterns based on three or five markers 5.