From the Guidelines
Laboratory diagnosis of Epstein-Barr virus (EBV) infection primarily relies on serological testing for specific antibodies, with the most recent and highest quality study recommending EBV antibody testing for IgG and IgM to viral capsid antigen (VCA) and Epstein-Barr nuclear antigen (EBNA) 1.
Key Diagnostic Tests
- Heterophile antibodies using the monospot or Paul-Bunnell test, which is rapid but has lower sensitivity in children under 4 years old
- Specific EBV antibody testing, including:
- VCA IgM (indicating acute infection)
- VCA IgG (past or current infection)
- EBNA IgG (past infection)
- PCR testing for viral DNA in blood or saliva, which offers high sensitivity for active infection and is particularly useful in immunocompromised patients
Interpretation of Test Results
- A typical acute infectious mononucleosis pattern shows positive VCA IgM and IgG with negative EBNA IgG, while past infection shows positive VCA IgG and EBNA IgG with negative VCA IgM
- The presence of VCA IgM (with or without VCA IgG) antibodies in the absence of antibodies to EBNA indicates recent primary infection with EBV 1
- The presence of EBNA antibodies indicates infection more than 6 weeks from the time of the sample and therefore not likely implicating EBV as a cause 1
Additional Diagnostic Considerations
- Complete blood count typically reveals lymphocytosis with atypical lymphocytes, and liver function tests may show mild transaminitis
- These tests help distinguish EBV from other causes of mononucleosis syndrome such as CMV or toxoplasmosis, allowing for appropriate management of this usually self-limiting infection
- In immunocompromised patients, increases in EBV viral load detected by NAAT in peripheral blood may be present before the development of EBV-associated lymphoproliferative disease 1
From the Research
Laboratory Diagnosis of Epstein-Barr Virus (EBV) Infection
The laboratory diagnosis of EBV infection can be achieved through various methods, including:
- Serological tests to detect antibodies against EBV antigens, such as viral capsid antigen (VCA) and Epstein-Barr nuclear antigen (EBNA-1) 2, 3, 4, 5
- Heterophile antibody test to diagnose primary EBV infection 3, 5
- Enzyme immunoassays (EIA) to detect IgG and IgM antibodies against VCA and EBNA-1 2, 4
- Western blot to detect antibodies against EBV antigens 6
- Polymerase chain reaction (PCR) to detect EBV DNA in various samples, including cerebrospinal fluid and biopsy tissues 6, 5
- In situ hybridization (ISH) of EBV-encoded RNA (EBER) in biopsy tissues to detect EBV involvement in tumors 6
Interpretation of EBV Serological Patterns
The interpretation of EBV serological patterns can be challenging due to the presence of multiple antibodies and antigens. However, studies have developed evidence-based tools to aid in the interpretation of EBV serologies, including:
- The use of tables to interpret EBV serological patterns based on the presence of three or five markers 3
- The combination of negative IgG anti-EBNA and low-avidity IgG anti-VCA to diagnose primary EBV infection 2
Diagnostic Performance of EBV Assays
The diagnostic performance of EBV assays has been evaluated in various studies, including: