The B. henselae Immunofluorescence Assay (IFA) is used to detect antibodies to B. henselae in human serum. Infections with B. henselae have been associated with Cat Scratch Disease, bacillary angiomatosis, peliosis hepatis, and bacteremia. Titers rise during the first two–to–four weeks of illness and decline over the next six–to–12 months. This test is unavailable for patients over 65 when ordered through physician services.