False-positive results occur less than once out of every 200 positive tests. These serological assays cannot be done on animals that have been vaccinated for Johne's disease as this will cause false-positive test results. Serum collected from a clotted blood sample and placed in a leak-proof plastic container is preferred. Serum separator tubes shipped after centrifugation are acceptable.
Overnight mail is also acceptable.
Results are reported as positive, negative, or suspect based on established interpretation criteria. This number is a measure of the amount of antibody to M. paratuberculosis in the serum sample. In general, higher levels of serum antibody indicate more advanced M. paratuberculosis infections and suggest that clinical signs of Johne's disease in the animal will begin soon, if they haven't already. Results are provided within 4 working days of receiving the sample, and, on request, will be sent by fax at no extra charge. Copyright 1996 by the Board of Regents of the University of Wisconsin System.