Lab Dept:

Microbiology/Virology

Test Name:

STREP GROUP A CULTURE

General Information

Lab Order Codes:

TCS

Synonyms:

Culture, for Group A Strep Only; Strep Culture; Beta Strep Culture; Culture, Strep A; Streptococcus Group A Culture

CPT Codes:

87081 – Culture, presumptive, pathogenic organisms, screening only

The following testing may be added if appropriate based on findings for organism identification (multiple additions are possible if more than one organism is identified).

87077 – Aerobic isolate, additional methods required for definitive identification, each isolate (if appropriate)
87206 – Smear, fluorescent and/or acid fast stain for bacteria, fungi, parasites, viruses or cell types (if appropriate)

Test Includes:

Culture for beta-hemolytic streptococci group A only. If other organisms are suspected, refer to Throat Culture, Routine.

Logistics

Lab Testing Sections:

Microbiology

Phone Numbers:

Minneapolis:

Saint Paul:

612-813-5866

651-220-6555

Test Availability:

Daily, 24 hours

Turnaround Time:

Results are reported within 1 – 2 days.

Special Instructions:

Specimen site and date/time of collection are required for specimen processing.

Specimen

Specimen Type:

Throat swab; Rectal swab; Vaginal swab

Container:

Swab transport medium

Collection:

Throat:

1. Depress tongue with tongue depressor.

2. Sample the posterior pharynx, tonsils, and inflamed areas with a sterile swab.

3. Place swab in transport medium.

Rectal swab:

1. Insert swab approximately 1 into anal canal.

2. Gently move the swab from side to side to sample the anal crypts.

3. If fecal contamination occurs, discard swab and use another to obtain specimen.

4. Place swab in transport medium.

Vagina:

1. Wipe away excessive amount of secretion or discharge.

2. Obtain secretions from mucosal membrane of the vaginal vault with a sterile swab.

3. If smear is also requested, collect on a separate swab.

4. Place swab in transport medium.

Storage/Transport:

Transport to the Microbiology Laboratory immediately at room temperature.

Sample Rejection:

Specimen with a transit time exceeding 24 hours after collection; specimen not submitted in appropriate transport container; improperly labeled specimen. If an unacceptable specimen is received, the physician or nursing station will be notified and another specimen will be requested before the specimen is discarded.

Interpretive

Reference Range:

No beta-hemolytic streptococci, group A isolated.

Methodology:

Culture

Contraindications:

Throat cultures are not advised for patients with inflamed epiglottis. Swabbing the epiglottis may precipitate acute respiratory obstruction.

Additional Information:

Streptococcus pyogenes (group A beta-hemolytic strep) is generally susceptible to penicillin and its derivatives, therefore, susceptibility need not be routinely performed. The principal reason for considering an alternative drug for individual patients is allergy to penicillin. Erythromycin, a cephalosporin, or clindamycin might be substituted in these cases. Patients allergic to penicillins may also be allergic to cephalosporins.

The majority of cases of pharyngitis are of viral etiology. At least 9 different viruses have been implicated, some of them producing symptoms indistinguishable from those of streptococcal infection such as severe sore throat with ulceration, exudate, and fever. Most cases of bacterial pharyngitis (up to 98%) are caused by beta-hemolytic streptococci, primarily those in group A.

There is some evidence that other beta-hemolytic streptococci, especially groups C and G and Arcanobacterium haemolyticum (Corynebacterium) may occasionally cause pharyngitis. These organisms are thought to be self-limiting and so far have not been associated with serious sequelae as seen with group A.

Any amount of group A streptococci will be reported.

Arcanobacterium haemolyticum (Corynebacterium and other beta-hemolytic streptococci (groups C and G) will be reported if present.

The presence og Group B streptococci will NOT be reported.

References:

Cook, JH, and M Pezzlo (1992). Specimen receipt and accessioning. Section 1. Aerobic bacteriology, 1.2.1-4. In HD Isenberg (ed) Clinical Microbiology Procedures Handbook. American Society for Microbiology, Washington DC

Miller, J Michael (1999) A Guide To Specimen Management in Clinical Microbiology, American Society for Microbiology, Washington DC

Miller, J Michael, and HT Holmes (1999) Specimen Collection, Transport, and Storage In PR Murray et al, (ed), Manual of Clinical Microbiology, 7th edition, American Society for Microbiology, Washington DC, pp 33-104

Updates:

3/24/2010: CPT Updates
10/11/2010: Test name updated, previously listed as Throat Culture, Group A Streptococci Only. Listing now includes information for throat, stool and vaginal sources.