Positive urinary antigen tests for Streptococcus pneumoniae in community-acquired pneumonia: a 7-year retrospective evaluation of health care cost and treatment consequences.

A positive pneumococcal urinary antigen test (PUAT) for Streptococcus pneumoniae allows an early switch from empiric to targeted treatment in hospitalised community-acquired pneumonia (CAP) patients. The economic and treatment consequences of this widespread implemented test are, however, unknown. We retrospectively evaluated all tests performed since its introduction in two teaching hospitals. Data on patient characteristics, treatment, admission and outcome were retrieved from the electronic patient files. Test benefits were expressed as the number of days that targeted therapy (i.e. penicillin) was administered to hospitalised CAP patients due to a positive PUAT. This calculation was based on the timing of the PUAT and the initiation of targeted therapy. Subsequently, we performed two direct cost analyses from a hospital perspective, first including tests performed for CAP only, and second including costs of all (excessive) tests. Between 2005 and 2012, 3,479 PUATs were performed, of which 1,907 (55 %) were for CAP. A total of 1,638 PUATs (86 %) were negative and 269 (14 %) were positive. Fifty-two (19 %) positive tests were excluded. In 75 (35 %) of the 217 remaining positive tests, a positive PUAT led to targeted treatment during 293 cumulative admission days. Testing costs for CAP only were €131 per targeted treatment day. These costs were €257 if local protocol dictated PUAT use for all CAP cases, as opposed to €72 if the test was reserved for severe cases only. When including all tests, PUAT costs were €254 per targeted treatment day. Therefore, improving the selective use of the PUAT in hospitalised CAP patients may lead to increased (cost-)efficiency.