EBV serology (Blood)

Diagnostic Use

Epstein-Barr virus (EBV) serology

Background
Infectious mononucleosis (IM) is the best-known clinical presentation of Epstein-Barr Virus (EBV) infection. IM usually begins with malaise, headache and fever followed by development of pharyngitis and cervical lymphadenopathy. Patients usually have a peripheral blood lymphocytosis of predominantly variant (atypical) lymphocytes. The majority of patients have a mild hepatitis and splenomegaly occurs in up to 50%. Acute symptoms resolve in 1-2 weeks, but fatigue often persists for months.

The incidence of clinically apparent IM is greatest when primary infection is delayed until the second decade of life. In developed countries, 50% of the population is infected with EBV infection by 5 years of age; the remaining susceptible population is usually infected before 25 years. Only around 10% of infections in infants and children are accompanied by a mononucleosis syndrome compared with 50-70% of infections in teenagers and young adults.

EBV Serology

VCA (viral capsid antigen) IgM antibodies are usually present at the onset of clinical illness because of the long incubation period (30-50 days) and persist for 2-4 months, occasionally longer. Their presence is suggestive of recent infection. However, other herpesviruses (e.g. CMV) may also induce IgM antibodies that cross-react with EBV antigens.

VCA IgG antibodies appear at the same time as IgM but persist for life; they are a marker of previous EBV infection. EA (early antigen) IgG appear as VCA IgM peaks and are present in around 70-80% of infected people.

EBNA (anti-EB nuclear antigen) antibodies appear 6-12 weeks after the onset of symptoms and persist for life; their presence early in the course of an illness excludes acute EBV infection. Some people infected with EBV never develop EBNA antibodies but will have VCA IgG to indicate their previous infection

Particularly when investigating an infectious mononucleosis syndrome in patients outside the typical 15-24 years age group, specific EBV serology rather than a monospot test alone is suggested. Children are commonly heterophile antibody negative and in older patients, EBV serology has the advantage of excluding patients with a previous EBV infection.

For Middlemore Requests –
EBNA IgG and VCA IgM will be routinely tested on all requests. Since EBV infection is so common, the pattern of EBNA IgG positive and VCA IgM negative is expected in most adults >25 years.

VCA/EA IgG will be automatically added if the profile from the 1st 2 markers is anything other than EBNA IgG positive/VCA IgM negative.

For Waitemata Requests –
Initial testing is age dependant, additional testing will be added automatically dependant of initial results.

For further information about EBV serology contact:

Dr Dragana Drinkovic, Clinical Microbiologist 021 784 612
Dr Matt Rogers, Clinical Microbiologist 021 524 605