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Beaumont Laboratory

Strep Screen, Group A

Throat, Pharynx, Pharyngitis, Rapid Strep Test, Rapid Strep A Screen, Rapid Strep A Screen Antigen, Strep A Screen (Rapid), Strep Screen, Group A Strep (Rapid Antigen Test), Antrim #40766, EPIC: LAB5472, SOFT: AGSSA

Specimen Collection Criteria

Collect: ESwab Specimen. Carefully swab the posterior pharynx and both tonsils, then place in the ESwab transport system.

Physician Office/Drawsite Specimen Preparation

Maintain swab specimens in ESwab transport system at room temperature (20-26°C or 68-78.8°F) until transport.

Preparation for Courier Transport

Transport: Swab in ESwab transport system, at room temperature (20-26°C or 68-78.8°F).

Rejection Criteria

  • Specimens collected with calcium alginate swabs.
  • Specimens submitted in amies charcoal.

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 24 hours
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Room Temperature (20-26°C or 68-78.8°F): 7 days

Laboratory

Farmington Hills Microbiology Laboratory.
Grosse Pointe Microbiology Laboratory.
Royal Oak Microbiology Laboratory.
Troy Microbiology Laboratory.

Performed

Sunday - Saturday, 24 hours a day.
STAT results available within 1 hour of receipt in the Laboratory.
Routine results available within 24 hours of receipt in the Laboratory.

Reference Range

Negative.

Test Methodology

Rapid Chromatographic Immunoassay.

Interpretation

  • Rapid Strep Screen testing has been reported to detect 70-85% of cases of Group A Streptococcus (GAS).
  • A negative Strep Screen result will reflex to Group A Strep by Nucleic Acid Amplification for patients less than 16 years of age.

Clinical Utility

Detection of Streptococcus pyogenes (Group A) antigen in pharyngeal specimens aids in the rapid diagnosis of pharyngitits due to Group A Streptococcus.

Clinical Disease

  • Streptococcus pyogenes is the most common bacterial pathogen implicated in pharyngitis. The principal manifestations of S. pyogenes are strep throat, scarlet fever, and skin infections (impetigo and cellulitis). Necrotizing fasciitis (the so called flesh-eating bacterial infection) has also been caused by S. pyogenes. Rapid diagnosis and treatment of S. pyogenes infections are necessay to prevent complications associated with these infections. The most common complications include acute rheumatic fever and acute glomerulonephritis. Rheumatic fever may occur after strep throat in about 2-3% of cases. Glomerulonephritis may follow either pharyngeal or skin infection. The most common symptoms of streptococcal pharyngitis include an abrupt onset of sore throat, malaise, headache, and a fever greater than 101°F. The throat is red and may have a grayish-white exudate on the tonsils. Additionally, children with strep throat often complain of a stomachache.
  • Scarlet fever is caused by an exotoxin produced by some beta-hemolytic Group A Streptococcus. The symptoms include a skin rash on the upper chest beginning on the second day of illness. The rash fades within a week and the skin may peel.
  • Impetigo is a superficial cutaneous infection characterized by crusted lesions. It typically occurs in late summer or early fall. It is most common in tropical or semitropical climates.
  • Necrotizing fasciitis is a life-threatening, and sometimes fatal disease that affects previously healthy patients. Symptoms include fever, severe pain, redness and swelling at the wound site. People with chronic illness are at higher risk of acquiring invasive disease. Cuts, wounds, and chickenpox provide an opportunity for bacteria to enter.
  • Toxic Shock Syndrome is usually caused by toxin 1 of S. aureus. Rarely Streptococcus pyogenes may also cause Toxic Shock Syndrome.

Epidemiology

Streptococcal pharyngitis occurs year-round in temperate climates, but the incidence peaks in the winter and spring months. Infections can occur in any age group but most cases occur among school-age children.

Transmission

Streptococcal infections are spread from person to person via inhalation of S. pyogenes laden respiratory droplets. Foodborne and milkborne transmission has also been described. A number of individuals, particularly school-age children, carry S. pyogenes without signs of illness. Carriers are culture positive and seronegative.

Reference

  1. Spellerberg, B. and C. Brandt. 2015. Streptococcus. Manual of Clinical Microbiology. 11th edition. ASM Press. Washington, D.C.

CPT Code

87880.

Test Codes

Antrim #40766, EPIC: LAB5472, SOFT: AGSSA

Last Updated

11/02/2017

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This directory currently reflects information only for specimens collected and/or processed at the Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.