Which Epstein‑Barr virus (EBV) antibodies should be ordered from a blood sample?

EBV Antibody Testing in Blood

Order a three-antibody panel consisting of VCA IgM, VCA IgG, and EBNA antibodies—this combination definitively distinguishes acute from past EBV infection and represents the gold standard for serologic diagnosis. 1, 2

Core Antibody Panel

The essential EBV antibodies to order from blood are:

• Viral Capsid Antigen (VCA) IgM antibodies – Indicates acute or recent primary infection 1, 2
• Viral Capsid Antigen (VCA) IgG antibodies – Appears early in acute infection and persists for life 1, 2
• Epstein-Barr Nuclear Antigen (EBNA) antibodies – Critical for timing the infection; develops 1-2 months after primary infection and persists lifelong 1, 2

Additional Antibodies in Specific Contexts

For suspected chronic active EBV infection (CAEBV), add:

• Early Antigen (EA-D) antibodies – Markedly elevated titers (≥1:160) suggest CAEBV when combined with very high VCA IgG (≥1:640) 3, 1
• IgA antibodies to VCA and/or EA – Frequently present in CAEBV and support the diagnosis 3, 1, 2

Interpretation Algorithm

For acute primary infection:

• VCA IgM positive + VCA IgG positive + EBNA negative = Acute primary EBV infection 1, 2

For past infection:

• VCA IgG positive + EBNA positive + VCA IgM negative = Past infection (>6 weeks prior), making EBV unlikely as cause of current symptoms 1, 2

For CAEBV (rare):

• VCA IgG ≥1:640 + EA IgG ≥1:160 + persistent mononucleosis-like symptoms + positive IgA to VCA/EA 3, 1, 2

Special Population Considerations

In immunocompromised patients (transplant recipients, HIV-infected individuals, congenital immunodeficiencies):

• Quantitative EBV viral load by nucleic acid amplification test (NAAT) is preferred over serology alone 1, 4, 2
• EBV DNA >10^2.5 copies/mg DNA in peripheral blood mononuclear cells indicates active infection 1, 2
• Serial viral load monitoring is essential regardless of antibody results due to lymphoproliferative disease risk 1, 2

In children under 10 years:

• Proceed directly to EBV-specific antibody testing rather than relying on heterophile (Monospot) tests, which have markedly higher false-negative rates in this age group 1, 4, 2

Critical Pitfalls to Avoid

• Do not order EBV testing from throat swabs – EBV persists in throat secretions for weeks to months after infection and does not confirm acute infection 1, 4
• Recognize that 5-10% of EBV-infected patients fail to develop EBNA antibodies – This should be considered when interpreting results 1, 4
• VCA IgG alone cannot distinguish recent from remote infection – Always order the complete panel including VCA IgM and EBNA 4
• False-positive VCA IgM can occur – Specificity improves from 49% to 97% when combined with EBNA testing 5

Enhanced Diagnostic Accuracy

IgG avidity testing can be added when serology remains equivocal:

• Low-avidity VCA IgG + negative EBNA = 100% sensitivity and specificity for acute infection 5
• High-avidity VCA IgG effectively excludes recent primary infection 5, 6
• Particularly useful in immunocompromised patients to differentiate primary infection from reactivation 7

When to Order EBV Testing

• Clinical features suggestive of infectious mononucleosis with negative heterophile antibody test 1
• Evaluating for EBV-associated lymphoproliferative disease in immunocompromised patients 1
• Persistent fever, lymphadenopathy, hepatosplenomegaly >10 days 1
• Markedly elevated transaminases (>10x normal) suggesting EBV-associated acute hepatitis 1
• CNS involvement with suspected EBV encephalitis (order both serum antibodies and CSF PCR) 1