This test measures the level of antibodies for Rabies.
A "titer" represents a measure of concentration. The term titer is used to represent how much of a specific type of antibody is circulating in the blood at any given moment.
A titer test is not an injection, shot, or vaccination. Instead, a titer test is the blood test that measures the titer level. Titer tests measure a level of specific antibodies to diseases in your blood. Antibodies can get into your blood through natural exposure to a disease, or through vaccination.
Titer tests are used as a measure of immunity to certain diseases. People who work in certain settings, such as hospitals or medical clinics, are at an increased risk for being exposed to certain diseases. As a result, many institutions want proof of a certain antibody level or vaccination for certain diseases prior to stepping into those settings.