Comparison of a clinic-based ELISA test kit with the immunofluorescence test for the assay of Ehrlichia canis antibodies in dogs

The "gold standard" for the detection of antibodies to Ehrlichia canis, the cause of canine monocytic ehrlichiosis (CME), is the indirect immunofluore scence antibody (LFA) test. The LFA test however is generally available onl y in selected laboratories and requires extensive equipment and trained per sonnel. A double-blind study was conducted to compare the ability of an in- clinic standardized enzyme-linked immunosorbent assay (ELISA) test kit to m easure E. canis IgG antibodies in dogs compared with the standard IFA techn ique. A good correlation was found between the 2 techniques (r(2) = 0.8793; P < 0.0001). Evidence for the sensitivity of the ELISA technique for the e arly detection of E. canis IgG antibodies was demonstrated by comparing the appearance of E. canis antibody titers by the IFA and ELISA techniques aft er artificial infection of 2 sets of dogs. in both experimental infections, both tests were equally sensitive for the early detection of IgG antibodie s against E. canis, and the results correlated well with the appearance of fever and clinical signs. Proposed application of the in-clinic ELISA test is to aid in the diagnosis of CME.