Used to aid in the presumptive diagnosis of pneumococcal pneumonia in conjunction with culture for Streptococcus pneumoniae.

Streptococcus pneumoniae vaccine may cause false positive results in the urinary antigen test. It is recommended that this test not be administered within 5 days of receiving the S. pneumoniae vaccine.

Streptococcus pneumoniae is responsible for at least 500,000 cases of pneumococcal pneumonia in the United States annually with infected patients often requiring hospitalization.  It is the leading cause of community-acquired pneumonia and may be the most important agent in community-acquired pneumonia of unknown etiology.  Pneumococcal pneumonia has a mortality rate as high as 30%, depending on bacteremia, age, and underlying disease.  S. pneumoniae infection can lead to bacteremia, meningitis, pericarditis, empyema, purpura fulminans, endocarditis, and/or arthritis if not properly diagnosed and treated.  Empirical treatment of suspected pneumonia can lead to indiscriminate use of antibiotics, a practice known to increase bacterial resistance.



Classification based on sputum culture is controversial, with oropharyngeal carriage of pneumococci in healthy individuals and inadequate sputum specimens contributing to an undetermined number of both false positive and false negative results.  Serology requires convalescent sera to document a rise in antibody titer and typically does not provide diagnostic information early enough to be clinically relevant.  Diagnosis of pneumococcal pneumonia by blood culture is useful in only the 10-30% of the pneumococcal pneumonia patients who became bacteremic.  Invasive specimens, such as those obtained by bronchioalveolar lavage (BAL) or transtracheal aspiration (TTA), are generally considered to be the most reliable in determining the etiology of pneumonia, and isolation of pneumococci from these specimens is proof of pneumococcal origin.  However, invasive techniques, which involve some risk, are not routinely used to diagnose pneumococcal and other typical pneumonias. 



The Streptococcus pneumoniae Urinary Antigen Test is an in vitro rapid immunochromatographic (ICT) assay for the detection of S. pneumoniae antigen in urine specimens from patients with symptoms of pneumonia.  It is intended to aid in the presumptive diagnosis of pneumococcal pneumonia in conjunction with culture and other methods.  The manufacturer’s stated sensitivity and specificity is 86% and 94%, respectively.



A negative antigen result does not exclude infection with S. pneumoniae since the antigen may not be present in urine in early infection, and the level of antigen present may be below detectable limits of the test. Therefore, the results of this test as well as culture results, should be used in conjunction with clinical findings to make an accurate diagnosis.



The Streptococcus pneumoniae Urinary Antigen Test has not been evaluated on patients taking antibiotics for greater than 24 hours or on patients who have recently completed an antibiotic regimen.



Streptococcus pneumoniae vaccine may cause false positive urinary antigen results in the 48 hours following vaccination.  Hence, it is recommended that the urinary antigen test not be administered within 5 days of receiving the vaccine.  



In a seven-center prospective study, the method had a sensitivity of 90% and a specificity ranging from 71% to 78% compared with positive blood cultures in 215 inpatients and outpatients with lower respiratory tract symptoms of pneumoncoccal pneumonia.



Streptococcus mitis shares the antigen against which the Streptococcus pneumoniae Antigen test is directed therefore cross-reactivity with this organism can be expected.

Streptococcus mitis which is common in the oropharnygeal flora shares the antigen against which the Streptococcus pneumoniae Antigen test is directed therefore cross-reactivity with this organism can be expected.

Immunochromatographic assay - for the qualitative detection of Streptococcus pneumoniae soluble antigen in urine specimens from patients with symptoms of pneumonia.