DefinitionThis blood test looks for antibodies against Francisella tularensis, the bacteria that cause the disease tularemia.Alternative NamesTularemia test; Serology for Francisella tularensisHow the test is performedAntibodies defend the body against bacteria, viruses, fungi, or other foreign substances, calledantigens. Certain cells cause the body to produce antibodies during an active infection.When you first get sick, few antibodies may be detected. Antibody production increases during the course of an infection. For this reason, antibody tests are often repeated several weeks after the first test is done, so the results can be compared. A rising level of antibodies tells the health care provider that there is indeed an infection.This test specifically looks for antibodies to F. tular