Group B Strep PCR

Sunquest Code:GBSPCR  
Epic Code:LAB3495Epic Name:Group B Strep PCR
Synonyms:GBS; GBSPCR; Beta Strep; Streptococcus; Genital; B streptococcus
Methodology:Automated polymerase chain reaction (PCR)
Turnaround Time:Performed 7 days a week. Results are reported within 1 day.
Associated Links:

IDDL (Microbiology/Virology) Collection Container Guidelines

Collection Instructions

Specimen:Females: Vaginal or vaginal/rectal swab
Container:CoPan ESwab with larger swab (CoPan ESwab with smaller swab)
Collection Instructions:Wipe away excessive vaginal secretions. Insert the swab into the vagina and sample secretions from the mucosa. Insert the same swab beyond the anal sphincter and rotate. Replace the swab in its container and label with patient's identification.
Contraindications:Patients who have used systemic or topical (vaginal) antibiotic treatment in the week prior, as well as patients diagnosed with placenta previa, should not be tested with the Xpert GBS LB assay.

Processing and Shipping

Specimen Processing:Store swab at refrigerated temperature for up to 6 days. Swabs stored at room temperature are stable for 48 hours.
Shipping Instructions:Ship swab at refrigerated temperature.
Test Performed at or Referral Lab Infectious Diseases Diagnostic Laboratory  (Fairview Range - FRMC, UMMC-East Bank)


Reference Range:
Negative for group B streptococcus by PCR.  
Detect group B streptococcus in the genital tracts of expectant mothers. Identify infants at risk for infection and guide intrapartum administration of antibiotics. One approach has been adopted to reduce this disease: Guidelines advocate all pregnant women have a vaginal/rectal screening test for GBS between 35 and 37 weeks gestation.

Screening Based Strategy
Perform vaginal/rectal screen at 35-37 weeks.
  • If positive, administer intrapertum antibiotics
  • If results unknown (delivery <37 w), administer intrapartum antibiotics
  • If results unknown (delivery > 37 w), refer to risk based strategy
  • If negative, do not administer intrapartum antibiotics

*Consensus Guidelines for the Prevention of Perinatal Group B Streptococcal Disease (from the Centers for Disease Control and Prevention), Atlanta, GA.

Susceptibility testing is automatically initiated on all specimens that are positive for group B streptococcus by PCR.    

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