Epstein Barr virus (EBV)

The commonest symptoms are feeling generally unwell, fever, sore throat (often with exudate/tonsillitis) and cervical lymph node enlargement. Rash can occur but is uncommon unless beta-lactam antibiotics have been given.

• Many primary (acute) infections are minimally symptomatic and go undiagnosed.
• Most patients get mild liver test derangement, and about half get splenic enlargement.

Fatigue can persist in some patients for months after initial infection. This is sometimes incorrectly labelled as ‘chronic EBV infection’, whereas it should be considered a ‘post-viral’ effect. True chronic EBV infection is very rare, and is characterised by ongoing IM-type symptoms e.g. fever, lymphadenopathy, deranged liver tests, low white blood cell count.

Laboratory confirmation of EBV infection is not usually required in young people with typical symptoms that self-resolve.

• Mimics to consider: HIV, syphilis. Toxoplasmosis and CMV infection if pregnant. Other causes of lymphadenopathy if persistent e.g. malignancy, TB.
• Lymphocytosis with atypical lymphocytes are consistent with, but not specific for, EBV.

Request EBV serology

EBNA IgG develops slowly (6-12 weeks) after primary infection, so is a marker of past infection. Its presence early in the course of an illness means acute EBV is not the cause.

• Reasonable sensitivity – negative result makes past infection unlikely, however 5-10% of people may never develop EBNA IgG
• Excellent specificity – positive result confirms past infection

VCA IgG indicates infection at some point in time (can be acute or past infection).

• Excellent sensitivity – negative result excludes infection, unless very early in illness
• Excellent specificity – positive result confirms infection at some stage

VCA IgM is used to indicate primary (acute) infection

• Good sensitivity – negative result makes primary infection unlikely
• Poor specificity – positive result doesn’t necessarily indicate acute infection

IgM can remain positive from old infection or occur with unrelated illnesses. The combination of positive VCA IgG and IgM with a negative EBNA IgG in a person with compatible symptoms makes primary EBV likely.

Heterophile antibody (Monospot, Paul Bunnell)

• Still used in some labs, however we no longer offer, as false positives can occur in other illnesses, as can false negatives particularly in early infection and children.

EBV DNA (EBV viral load, EBV PCR)

• Cannot differentiate between primary and past infection and is reserved for specialist use, usually in severely immunocompromised patients.