An enzyme immunoassay for the qualitative and semiquantitative determination of IgG-class antibodies to Epstein-Barr virus nuclear antigen type 1 (EBV-EBNA-1) in serum. The DRG Epstein-Barr Virus (EBNA-1) IgG ELISA Kit is a solid phase enzyme-linked immunosorbent assay (ELISA) Microtiter wells as a solid phase are coated with recombinant EBV nuclear antigen type 1. Diluted patient specimens and ready-for-use controls are pipetted into these wells. During incubation EBNA-1-specific antibodies of positive specimens and controls are bound to the immobilized antigens. After a washing step to remove unbound sample and control material horseradish peroxidase conjugated anti-human IgG antibodies are dispensed into the wells. During a second incubation this anti-IgG conjugate binds specifically to IgG antibodies resulting in the formation of enzyme-linked immune complexes. After a second washing step to remove unbound conjugate the immune complexes formed (in case of positive results) are detected by incubation with TMB substrate and development of a blue color. The blue color turns into yellow by stopping the enzymatic indicator reaction with sulfuric acid. The intensity of this color is directly proportional to the amount of EBNA-1-specific IgG antibody in the patient specimen. Absorbance at 450 nm is read using an ELISA microtiter plate reader.