Sensitivity, Specificity, and Positivity Predictors of the Pneumococcal Urinary Antigen Test in Community-Acquired Pneumonia.

Rationale: Detection of the C-polysaccharide of Streptococcus pneumoniae in urine by an immune-chromatographic test is increasingly used to evaluate patients with community-acquired pneumonia.Objectives: We assessed the sensitivity and specificity of this test in the largest series of cases to date and used logistic regression models to determine predictors of positivity in patients hospitalized with community-acquired pneumonia.Methods: We performed a multicenter, prospective, observational study of 4,374 patients hospitalized with community-acquired pneumonia.Measurements and Main Results: The urinary antigen test was done in 3,874 cases. Pneumococcal infection was diagnosed in 916 cases (21%); 653 (71%) of these cases were diagnosed exclusively by the urinary antigen test. Sensitivity and specificity were 60 and 99.7%, respectively. Predictors of urinary antigen positivity were female sex; heart rate ≥125 bpm, systolic blood pressure <90 mm Hg, and SaO2 <90%; absence of antibiotic treatment; pleuritic ...