The U.S. Department of Agriculture's Animal and Plant Health Inspection Service is amending its brucellosis regulations. This amendment will add the fluorescence polarization assay (FPA) to the list of approved brucellosis tests in cattle, bison and swine, according to an APHIS news release.

APHIS has determined that a rapid diagnostic detection test that uses fluorescence polarization technology will be highly useful in detecting the presence of Brucella antibodies.

A technician performs this test by first measuring a sample of animal serum for natural fluorescence using a specialized polarization instrument. Next the technician adds an antigen extracted from Brucella abortus cells that have been coupled with a fluorescent identifier.

The sample is measured again to determine a change in polarization that would indicate the presence of the disease. Test results are conclusive, producing either a negative or positive result. This test provides a cost-effective, accurate, quick and simple-to-perform means of determining if the disease is present in cattle, bison and swine.

The FPA test can be used as a screening or confirmatory test and as a stand-alone test if no other tests are available for confirmatory results for brucellosis classification of animals.

In trials summarized in four scientific publications, the FPA test has proven to be faster and as accurate as other official tests used for diagnosis of brucellosis. Although the FPA test is quicker and more cost effective than some of the brucellosis tests, confirmatory tests are performed to provide assurance that the classification of the animal in question is correct.