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Pneumococcal and Legionella Urinary Antigen Tests in Community-acquired Pneumonia: Prospective Evaluation of

Shawna Bellew1, Carlos G Grijalva1, Derek J Williams1

  • 1Vanderbilt University Medical Center, Nashville, Tennessee.

Clinical Infectious Diseases : an Official Publication of the Infectious Diseases Society of America
|September 29, 2018
PubMed

Insights

Current guidelines for urinary antigen tests in community-acquired pneumonia have low accuracy. Future guidelines should refine strategies for Streptococcus pneumoniae and Legionella pneumophila testing in adults.

Area of Science:

  • Infectious Diseases
  • Clinical Microbiology
  • Pulmonology

Background:

  • Community-acquired pneumonia (CAP) guidelines by IDSA/ATS recommend urinary antigen tests (UATs) for Streptococcus pneumoniae (SP) and Legionella pneumophila (LP).
  • These recommendations are based on expert opinion and lack rigorous evaluation.
  • The diagnostic utility of current UAT indications in CAP requires assessment.

Purpose of the Study:

  • To evaluate the sensitivity and specificity of IDSA/ATS urinary antigen test indications.
  • To assess the accuracy of current guidelines in identifying patients with positive SP and LP UATs.
  • To inform future recommendations for UAT use in adult CAP.

Main Methods:

  • Utilized data from a multicenter, prospective surveillance study of hospitalized adults with CAP.
  • Analyzed SP and LP UAT results against IDSA/ATS recommended indications.
  • Employed 2x2 contingency tables and logistic regression to assess test performance and associated clinical factors.

Main Results:

  • Among 1941 patients, SP UATs were positive in 4.2% and LP UATs in 1.6%.
  • IDSA/ATS indications showed 61% sensitivity and 39% specificity for SP, and 63% sensitivity and 35% specificity for LP.
  • No strong clinical predictors for positive SP UATs were found; hyponatremia, fever, diarrhea, and recent travel were associated with positive LP UATs.

Conclusions:

  • Current IDSA/ATS indications for SP and LP urinary antigen testing in CAP exhibit poor sensitivity and specificity.
  • Existing guidelines are inadequate for effectively identifying patients who would test positive.
  • Future CAP guidelines necessitate revised strategies for selecting patients for urinary antigen testing.
Abstract

Keywords:
Legionellapneumococcalpneumoniaurine antigen test

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