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UATs for SP and LP in Community-acquired Pneumonia

Clin Infect Dis; ePub 2018 Sep 28; Bellew, et al

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.