Contribution of a urinary antigen assay (Binax NOW) to the early diagnosis of pneumococcal pneumonia

Clin Infect Dis. 2004 Jan 15;38(2):222-6. doi: 10.1086/380639. Epub 2003 Dec 18.


We evaluated the usefulness of a rapid urinary antigen test (Binax NOW; Binax) to detect Streptococcus pneumoniae for the early diagnosis of community-acquired pneumococcal pneumonia (PP) in 220 nonseverely immunosuppressed adults. We compared results of this test with those of sputum Gram staining. The rapid urinary antigen test showed limited sensitivity (65.9%; 95% confidence interval [CI], 51.4-80.4) but high specificity (100%; 95% CI, 99.7-100) for diagnosing PP. The test was more sensitive for patients with versus those without high-risk pneumonia (94% vs. 63%; P<.001) and for patients without versus those with demonstrative results of a sputum Gram stain (97% vs. 55%; P<.001), and it tended to be more sensitive for patients with versus those without bacteremic PP (92% vs. 74%; P=NS). Rapid urinary antigen testing permitted early diagnosis of PP in 26% more patients than did Gram staining but missed 22% of the rapid diagnoses initially identified by Gram staining. On the basis of our results, a sequential approach is proposed, with reservation of urinary antigen testing for high-risk patients for whom demonstrative results of a sputum Gram stain are unavailable.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antigens, Bacterial / urine*
  • Humans
  • Pneumococcal Infections / diagnosis*
  • Pneumonia, Pneumococcal / diagnosis*
  • Pneumonia, Pneumococcal / microbiology
  • Reagent Kits, Diagnostic*
  • Sensitivity and Specificity
  • Streptococcus pneumoniae / isolation & purification*


  • Antigens, Bacterial
  • Reagent Kits, Diagnostic