Recommended indications for Streptococcus pneumoniae (SP) and Legionella pneumophila (LP) urinary antigen testing (UAT) in the Infectious Diseases Society of America/American Thoracic Society (IDSA/ATS) community-acquired pneumonia (CAP) guidelines have poor sensitivity and specificity for identifying patients with positive tests, a recent study found. Researchers used data from a multicenter prospective surveillance study of adults hospitalized with CAP to evaluate the sensitivity and specificity of the IDSA/ATS UAT indications for identifying patients who test positive. SP and LP UATs were completed on all included patients. Findings included:
- Among 1,941 patients, UATs were positive for SP in 81 (4.2%) and LP in 32 (1.6%).
- IDSA/ATS indication had 61% sensitivity and 39% specificity for SP, and 63% sensitivity and 35% specificity for LP.
- Clinical characteristics associated with positive LP UATs were hyponatremia, fever, diarrhea, and recent travel; there were no features strongly associated with positive SP UATs.
Bellew S, Grijalva CG, Williams DJ, et al. Pneumococcal and Legionella urinary antigen tests in community-acquired pneumonia: Prospective evaluation of indications for testing. [Published online ahead of print September 28, 2018]. Clin Infect Dis. doi:10.1093/cid/ciy826.