Epstein-Barr Virus (EBV) Antibody Panel: VCA IgM, VCA IgG and EBNA IgG

The panel reports three antibodies made against Epstein-Barr virus, measured by immunoassay. VCA IgM (antibody to the viral capsid antigen) appears early in infection and usually disappears within weeks to a few months. VCA IgG appears during the acute illness and stays for life. EBNA IgG (antibody to the EBV nuclear antigen) is not present during the acute phase; it appears 2 to 4 months after symptoms begin and also stays for life. Quest reports each antibody as Negative, Equivocal or Positive, with an overall interpretation. The panel does not include the early antigen (EA) antibody.

People, most often teens and young adults, whose clinician wants to confirm or rule out a recent EBV infection as the cause of mono-like symptoms such as fever, sore throat, swollen neck lymph nodes and fatigue; people who want to know whether they have ever had EBV; and people whose clinician has asked for EBV status for another reason. It is not useful for screening healthy adults for an "active" EBV problem, because most adults are positive from a past infection.

When mono-like symptoms are present, or when a clinician asks for your EBV status. Antibodies can be undetectable very early in an illness, so if the first result is negative but symptoms suggest mono, a repeat test about 10 days to 2 or more weeks later may be advised. EBNA IgG takes 2 to 4 months to appear, which is what lets the panel separate a recent infection from an older one. No fasting is needed and the test can be done at any time of day.

Results are read as a pattern. All three antibodies negative: no sign of past or current EBV infection (you are considered susceptible). VCA IgM positive with EBNA IgG negative: consistent with a new or recent (primary) infection. VCA IgG and EBNA IgG positive with VCA IgM negative: a past infection, from several months to many years ago. This is the most common result in adults and does not mean the virus is causing current symptoms. Other combinations (for example, VCA IgG positive alone, or an equivocal value) can occur and are interpreted together with your symptoms and their timing; a repeat test may be suggested. Quest's reference ranges are VCA IgM negative below 36.00 U/mL (36.00-43.99 equivocal), and VCA IgG and EBNA IgG negative below 18.00 U/mL (18.00-21.99 equivocal). JustLabs results are informational; review them with a clinician, especially if you are unwell.