Identification of the causative organism of pneumonia can be difficult, and in practice is often not achieved. This may lead to inappropriately broad spectrum antibiotic treatment.
A Gram stain and culture of a well collected sputum can be very useful if a predominant organism is present. Streptococcus pneumoniae is the most common cause of bacterial pneumonia.
The S.pneumoniae antigen test performed on urine is able to detect infection with S.pneumoniae. In adults, the test has a sensitivity for detecting pneumococcal pneumonia of about 50 - 60%. The specificity is 97 - 100%. The sensitivity is increased in bacteraemic patients. The specificity of the test in adults allows for more directed therapy; however the specificity of the test in children is poor.
Transport specimen chilled at 2-8 deg C.