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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: Strep A Screen, Rapid Ag, Culture if Neg

Test Code(s): RSTREP / RAPDSC

CPT Code(s): 87880

Methodology: Immunoassay

Clinical Significance: Rapid screening for Group A Streptococci from throat swabs.  Culture on adult patients may not be needed.  Consider ordering Strep A Screen, Rapid Ag [RAPD] instead.

Days Performed: Daily, 24 hours.

Turnaround Time: Stat: 1 hour.
Routine: 4 hours.


Specimen Requirements

Specimen: Pharyngeal swab

Collection Instructions: Use standard specimen collection techniques.  

Culture swabs can be obtained from UWHC Central Supply.  The double swab required for this test is CS item #4005445.  If using single swab culturettes (CS item #1220190), please submit two.

Collection Container: Preferred: 2 CultureSwabs®

Specimen Transport: Store swabs in tightly capped tube. Transport to UWHC Core Laboratory (B4/220).

Unacceptable Criteria: Frozen swabs, swabs with calcium alginate or cotton tips or wooden shafts, and specimens greater than 72 hours post collection are not acceptable.

Stability: Ambient: 8 hours
Refrigerated: 3 days
Frozen: Not acceptable


Interpretation

This is a screening test only. A negative result may indicate either that the specimen obtained was negative for the presence of Group A Streptococci or that the amount of antigen extracted from the specimen is less than the analytical sensitivity of the test. The result should be interpreted in conjunction with clinical and other data available to the clinician. All specimens that test negative are sent to the UWHC Microbiology Lab for a Strep Culture.

Additional Information:

Culture on adult patients may not be needed.  The Infectious Diseases Society of America (IDSA) practice guidelines (2012) state that, because of the reduced sensitivity of rapid antigen tests and the importance of accurate detection, predominantly for prevention of rheumatic heart disease, culture confirmation of negative rapid antigen tests is recommended for pediatric patients.

 

The risk of infection is apt to be higher for parents of school-aged children and for adults whose occupation brings them into close association with children.

Strep A Antigen (Rapid Test)

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