How to Interpret an Epstein-Barr Test

When studying human diseases, your instructor may ask you to interpret the results of an Epstein-Barr test for a patient supposedly suffering from mononucleosis, or mono. When the Epstein-Barr virus is present in the system, the body produces a variety of antibodies. The first antibodies produced are immunoglobulin M (IgM) and immunoglobulin G (IgG) to the viral capsid antigen (VCA). The next antibody produced is an IgG antibody to the D early antigen (EA-D), and the final antibody produced, often after the infection has cleared, corresponds to the Epstein-Barr nuclear antigen (EBNA). The presences or absence of these antibodies, as well as their concentrations, allow you to determine the stage of a mono infection.

Instructions

• 1

  Analyze the test results for the presence of VCA-IgM. If VCA-IgM is present in the blood sample, an Epstein-Barr infection is present and active. If there is no VCA-IgM present, the infection may be more than 4 to 6 weeks old or the person may not have a mono infection.

• 2

  Analyze the test results for the presence of EA-D IgG. This antibody develops within a week of an active infection and disappears after two weeks. If the patient was treated for flu-like symptoms for two weeks before testing for mono, the EA-D IgG may have disappeared from the body. Both VCA antibodies are reliable diagnostic tools in this case.

• 3

  Analyze the test results for the presence of VCA-IgG. In the absence of both VCA-IgM and VCA-IgG, the patient has never had an infection and may not have an infection. VCA-IgG is present within a week of infection and persists for life. The presence of VCA-IgG only conclusively indicates a past infection.

• 4

  Analyze the test results for the presence of EBNA-IgG. This antibody appears 2 to 4 months after the body clears a mononucleosis infection and is present for life. The presence of this antibody with the presence of VCA-IgM indicates a recurrence of the infection. Without VCA-IgM, the patient's symptoms are the result of some other disease.

• 5

  Repeat the Epstein-Barr test in two to three weeks to determine if the concentration of VCA-IgG increases, decreases or stays the same. An increase in VCA-IgG indicates and active infection. A decrease indicates a clearing of the infection. A stable VCA-IgG level without the presence of VCA-IgM in the previous test and the presence of EBNA-IgG in both tests indicates a previous infection.