Streptococcus pneumoniae Antigen, Spinal Fluid
Rapid diagnosis of pneumococcal meningitis
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Streptococcus pneumoniae is the most frequently encountered bacterial agent of community acquired pneumonia, and can also be an agent of bacterial meningitis. Because of the significant morbidity and mortality associated with pneumococcal pneumonia, septicemia, and meningitis, it is important to have diagnostic test methods available that can provide a rapid diagnosis. In instances where empirical antibiotics are being considered prior to culture confirmation, antigen testing may be useful.
Note: According to the College of American Pathologists (CAP, IMM.41830), cerebrospinal fluid (CSF) samples collected to make an initial diagnosis and submitted for detection of Streptococcus pneumoniae antigen testing should also be submitted for routine bacterial culture. Mayo Medical Laboratories recommends that CSF bacterial cultures be performed at the originating site.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
A positive result supports a diagnosis of pneumococcal meningitis.
A negative result suggests that pneumococcal antigen is absent in the cerebrospinal fluid (CSF). However, infection due to Streptococcus pneumoniae cannot be ruled out since the antigen present in the specimen may be below the lower limit of detection of the test.
If pneumococcal meningitis is suspected, bacterial culture and Gram-stain analysis on CSF should be performed.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
A negative result does not exclude Streptococcus pneumoniae infection.
A diagnosis of Streptococcus pneumoniae infection must take into consideration all test results, culture results, and the clinical presentation of the patient.
Streptococcus pneumoniae vaccine may cause false-positive results, especially in patients who have received the vaccine within 5 days of having the test performed.
This assay has not been validated for use with body fluids other than urine or cerebrospinal fluid.
The performance of this assay in patients who have received antibiotics for >24 hours has not been established.
The accuracy of this assay has not been proven in small children.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Plouffe JF, Moore SK, Davis R, et al: Serotypes of Streptococcus pneumoniae blood culture isolates from adults in Franklin County, Ohio. J Clin Microbiol 1994;32:1606-1607
2. Johnston RB Jr: Pathogenesis of pneumonococcal pneumonia. Rev Infect Dis 1991;13:509-517