EBV Diagnostic Testing

Initial Testing Strategy

The American College of Physicians recommends beginning with a heterophile antibody test combined with a complete blood count with differential, but if the heterophile test is negative and clinical suspicion remains high, proceed immediately to EBV-specific antibody testing including VCA IgM, VCA IgG, and EBNA antibodies 1, 2
Order a rapid heterophile antibody test as the initial screening test in adolescents and adults with suspected infectious mononucleosis 1, 2
Obtain a complete blood count with differential to look for elevated white blood cell count with increased atypical lymphocytes, which is a hallmark of EBV-associated mononucleosis 1
The heterophile antibody becomes detectable between days 6-10 after symptom onset and peaks during weeks 2-3 of illness 2

For transplant recipients, HIV-infected individuals, and those with congenital immunodeficiencies, the Infectious Diseases Society of America recommends ordering quantitative EBV viral load testing by nucleic acid amplification test (NAAT) in peripheral blood rather than relying solely on serology 1, 2, 3
EBV DNA levels > 10^2.5 copies/mg DNA in peripheral blood mononuclear cells indicate active infection 1, 3
Post-transplant patients require EBV DNA surveillance due to high risk of lymphoproliferative disease 2

The Infectious Diseases Society of America explicitly states that heterophile tests are suboptimal and recommends EBV-specific antibody testing when these are negative 2
VCA IgM indicates acute or recent infection 1, 2
VCA IgG develops rapidly in acute infection and persists for life 1, 2
EBNA antibodies are critical for timing the infection; develops 1-2 months after primary infection and persists for life 1, 2

VCA IgM positive + EBNA antibodies absent = recent primary EBV infection (less than 6 weeks) 1, 2
EBNA antibodies present + VCA IgM absent = past infection (more than 6 weeks ago), making EBV unlikely as the cause of current symptoms 1, 2
Over 90% of normal adults have IgG antibodies to VCA and EBNA from past infection 2

CAEBV requires: (1) persistent or recurrent infectious mononucleosis-like symptoms, (2) unusual antibody patterns with raised anti-VCA and anti-EA, and (3) chronic illness that cannot be explained by other known disease processes 3
Markedly elevated VCA IgG titers (≥1:640) combined with elevated EA IgG (≥1:160) suggest CAEBV 1, 3
Positive IgA antibodies to VCA and/or EA are often demonstrated in CAEBV 1, 3

Collect serum specimens as soon as possible after symptom onset for serologic testing 1
For EBV DNA detection, use whole blood, peripheral blood lymphocytes, or plasma in EDTA tube at room temperature, transported within 2 hours 1

Do not order EBV testing from throat swabs—EBV can persist in throat secretions for weeks to months after infection and does not confirm acute infection 1, 2
Do not interpret the presence of EBNA antibodies as indicating acute infection; these develop 1-2 months post-infection and indicate past exposure 1, 2
Remember that 5-10% of infected patients, particularly immunocompromised individuals, may not develop EBNA antibodies despite infection 1, 2