Epstein-Barr Virus (EBV) IgG EIA

For the qualitative and semi-quantitative detection of human IgG antibodies to Epstein-Barr (EB) viral capsid antigen (VCA) in human serum by enzyme immunoassay. The test may be used in conjunction with other serologicals, as an aid in the diagnosis of infectious mononucleosis. These reagents have not received FDA clearance for use in testing blood or plasma donors. 

About Epstein-Barr Virus

Epstein-Barr virus (EBV) is the etiological agent of infectious mononucleosis (IM).¹ The designation of infectious mononucleosis classically refers to an Epstein-Barr virus-induced illness in young adults characterized by reactive blood smears, exudative pharyngitis, prominent cervical lymphadenopathy, and serologically detectable heterophile antibodies. These clinical manifestations can also be caused by a number of other pathogenic agents including cytomegalovirus, Toxoplasma gondii, rubella virus, hepatitis virus, human immunodeficiency virus (HIV), and uncommonly by drugs such as Halothane, Hydantoin, Dapasone, and Azulfidine. ^2,3,4

Diagnosis of acute EBV IM is generally confirmed by a positive heterophile antibody test. The severity of the disease, however, is not indicated by the relative titer of heterophile antibodies.⁵ In addition, difficulties in diagnosis arise when the heterophile antibody test is negative or when the clinical manifestations are atypical or unusually severe.

Heterophile-negative IM occurs in 10 to 20 percent of adults, and in even greater percentage of children. ^6,7 IM diagnosis in these individuals may be confirmed by the detections and identification of antibodies to specific EB antigens which include: viral capsid antigen (VCA), early antigens, diffuse and restricted (EA-D and EA-R), and Epstein-Barr nuclear antigen (EBNA).

IgG antibodies to VCA may be present early during EBV infection, but they persist indefinitely after the occurrence of clinical disease and may merely indicate EBV infection at some time in the past. IgM antibodies to VCA, on the other hand, are present in the circulation 1 to 6 weeks after the onset of EBV illness and usually disappear in 3 to 6 months. Thus the presence of VCA IgM usually suffices for the diagnosis of acute IM. Further verification may be obtained by testing for presence of antibodies directed against the other EBV-specific antigens, early antigen and EBNA. Heterophile antibody negative sera demonstrating VCA IgM and transient levels of antibody to early antigen are considered diagnostic for acute IM. In contrast, antibodies to EBNA appear late during IM infections, and IgG antibodies to EBNA may persist for years, even for life, and are indicative of the convalescent phase of IM infection.

Diluted samples are incubated in VCA antigen-coated wells. VCA IgG antibodies (if present) are immobilized in the wells. Residual sample is eliminated by washing and draining, and conjugates (enzyme labeled antibodies to human IgG) is added and incubated. If IgG antibodies to VCA are present, the conjugate will be immobilized in the wells. Residual conjugate in eliminated by washing and draining, and the substrate is added and incubated. In the presence of the enzyme, the substrate in converted to a yellow end product which is read photometrically.

Test performed by Eurofins DPT , 6933 S. Revere Parkway, Centennial, CO 80112. This test has not been cleared or approved for diagnostic use by the U.S. Food and Drug Administration. See package insert for more information.