Rapid diagnosis of pneumococcal pneumonia
Immunochromatographic Membrane Assay
Pneumococcal pneumonia is best diagnosed by sputum culture. For more information, see SPUTS / Bacterial Culture, Aerobic, Respiratory with Antimicrobial Susceptibilities, Varies.
Supplies: Urine Tubes, 10 mL (T068)
Container/Tube: Plastic, 10-mL urine tube
Specimen Volume: 2 mL
1. Collect a random urine specimen.
2. No preservative.
3. Excessively bloody or very turbid specimens containing protein, cells, or particulates will be canceled as they can inhibit the function of the test.
4. Centrifuging to remove particulates is not approved.
5. Specimens with any dyes or unnatural color are not acceptable and will be canceled.
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.
|Turbid Dyes/unnaturally colored||Reject|
|Specimen Type||Temperature||Time||Special Container|
|Urine||Refrigerated (preferred)||14 days|
Rapid diagnosis of pneumococcal pneumonia
Streptococcus pneumoniae is the most frequently encountered bacterial agent of community-acquired pneumonia (CAP). 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 provided for CAP without culture confirmation of S pneumoniae, antigen testing may be useful.
A positive result is indicative of pneumococcal pneumonia.
Negative for pneumococcal pneumonia, suggesting no current or recent pneumococcal infection. Infection due to Streptococcus pneumoniae cannot be ruled out since the antigen present in the sample may be below the detection limit of the test.
A negative result does not exclude Streptococcus pneumoniae infection.
A diagnosis of S pneumoniae infection must take into consideration all test results, culture results, and the clinical presentation of the patient.
S 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 more than 24 hours has not been established.
The accuracy of this assay has not been proven in small children.
1. Plouffe JF, Moore SK, Davis R, Facklam RR: Serotypes of Streptococcus pneumoniae blood culture isolates from adults in Franklin County, Ohio. J Clin Microbiol. 1994 Jun;32(6):1606-1607
2. Johnston RB Jr: Pathogenesis of pneumococcal pneumonia. Rev Infect Dis. 1991 May-Jun;13 Suppl 6:S509-S517. doi: 10.1093/clinids/13.supplement_6.s509
3. Janoff EN, Musher DM: Streptococcus pneumoniae. In Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020:2473-2491
The Binax NOW Streptococcus pneumoniae test is an immunochromatographic membrane assay used to detect pneumococcal soluble antigen in human urine and cerebrospinal fluid. Rabbit anti-S pneumoniae and anti-species antibodies are conjugated to visualizing particles that are dried onto an inert fibrous support. The resulting conjugate pad and the striped membrane are combined to construct the test strip.
To perform the test, a swab is dipped into the specimen, removed, and then inserted into the test device. Reagent A, a buffer solution is added from a dropper bottle. The device is then closed, bringing the sample into contact with the test strip. Pneumococcal antigen present in the sample reacts to bind anti-S pneumonia-conjugated antibody. The resulting antigen-conjugate complexes are captured by immobilized anti-S pneumoniae-conjugated antibody. The resulting antigen-conjugate complexes are captured by immobilized anti-S pneumoniae antibody, forming the sample line. Immobilized control antibody captures anti-species conjugate forming the control line.
Test results are interpreted by the presence or absence of visually detectable pink-to-purple colored lines. A positive test result, read in 15 minutes depending on the concentration of antigen present in the sample, will include the detection of both a sample and control line. A negative test result, read in 15 minutes, will produce only a control line, indicating that S pneumoniae antigen was not detected in the sample. Failure of the control line to appear, whether the sample line is present or not, indicates an invalid assay.(Package insert: BinaxNOW Streptococcus pneumoniae Antigen Card. Abbott Diagnostics Scarborough, Inc; 01/2020)
Monday through Friday
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.