In 1958, Centers for Disease Control and Prevention (CDC) scientists Robert Goldwasser and Robert Kissling adapted immunofluorescence techniques to develop the Direct Fluorescent Antibody (DFA) test for rabies that demonstrating 100 percent accuracy in field trials.

The test was pioneered by Dr. Robert Kissling and his team to rapidly identify the rabies virus in brain tissues. This method replaced slower, traditional techniques, offering rapid, reliable diagnosis for both animals and humans.

During the 50 years the direct fluorescent antibody (DFA) test has been used in the U.S., there has been no indication it has failed to provide accurate clinical information on the rabies status of an animal for the purposes of treating an exposed person.