Although it has been shown that EBV DNA can be detected in serum samples and may be useful in diagnosis of EBV-related disease, serum may not be the best sample for making a clinical diagnosis. This is particularly true for cases of nasopharyngeal carcinoma where EBV involvement is suspected. Heterophile antibody has rarely been associated with disease states other than infectious mononucleosis and the EBV-associated neoplasms. A single heterophile antibody titer is considered to have no relation to the severity of the disease, but sequential titer determinations may be useful in following the course of an individual patient. The heterophile test or mononucleosis slide test are probably the best for detecting acute EBV infection.
Negative results are more common in children.
If further testing is desired, collect additional specimens and retest every week or so. IgM antibodies to VCA are particularly sensitive and specific for IM, as VCA-IgM antibodies are rarely seen in the general population. Most individuals possess nearly peak titers of VCA-IgG antibodies by the time clinical symptoms of acute infection are apparent. Once present, IgG antibodies to VCA will persist for life. A gradual increase in EBNA antibody titer occurs during convalescence and near-peak titers are maintained for life.