2071. Epstein-Barr virus (capsid antigen, VCA), IgG antibodies

IgG antibodies to the EBV capsid antigen (VCA) indicate a current or past infection. They are a marker of the response after exposure to the virus. They are determined in cases of suspected mononucleosis, in pregnant women, in cases of immunosuppression, or to differentiate the phases of infection.

The Epstein-Barr virus (EBV, herpesvirus type 4) is one of the most common human viruses, infecting the vast majority of the population during their lifetime. The primary route of transmission is contact with bodily fluids, most commonly saliva. After initial infection (usually in childhood or adolescence), the virus remains latent in the body, periodically reactivating asymptomatically or with clinical manifestations.

EBV is the causative agent of infectious mononucleosis, an acute viral disease characterized by fever, sore throat, lymphadenopathy, and hepatosplenomegaly. The virus is also associated with chronic EBV syndrome, Burkitt's and Hodgkin's lymphomas, nasopharyngeal carcinoma, and lymphoproliferative complications in immunocompromised patients.

After infection, the immune system responds by producing specific antibodies. IgG antibodies to the viral capsid antigen (VCA-IgG) are among the first markers of the humoral immune response. They:

• appear early in infection (almost simultaneously with IgM);
• peak in the acute phase;
• and persist throughout life, providing immunological memory.

The presence of VCA-IgG indicates:

• past or active EBV infection (with concomitant IgM);
• development of an immune response and the presence of post-infection immunity;
• late phase or convalescence, especially in combination with EBNA-IgG (antibodies to the nuclear antigen).

Combined interpretation (IgM + IgG + EBNA):

• IgM (+), IgG (+), EBNA (–) → primary infection;
• IgM (–), IgG (+), EBNA (+) → previous infection (late stage);
• IgM (+), IgG (+), EBNA (+) → possible reactivation or protracted form.

• If infectious mononucleosis is suspected.
• To assess the serological status of a pregnant woman (EBV positivity or lack of immunity).
• For immunocompromised patients (HIV, oncohematology, transplantation) – as part of monitoring.
• To differentiate between the phases of EBV infection (along with IgM and EBNA).
• In cases of reactivation or chronic progression.

• Venous blood

In order to exclude factors that may affect the test results, we recommend to follow the preparation rules: