University of Wisconsin–Madison


Diagnostic testing based on the binding of antibody and antigen. The antibody is produced by an animal in response to infection and is found in serum (fluid portion of blood). The antigen, a portion of the infecting organism, is incorporated into the diagnostic test. In most cases of Johne’s disease, serology is most likely to detect an infected animal during later stages of the infection when antibody is most likely to be produced.