Laboratory Services

Group B Strep with Reflex to Susceptibility

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Updated Test Information:

Test Description
Group B Strep with Reflex to Susceptibility

Group B Strep Screen, GBS culture, GBS screen, Prenatal screen, GBS susceptibility, Group B Strep Susceptibility

Test ID
General Information

Beta-hemolytic Group B Streptococcus (GBS), also known as Streptococcus agalactiae, is important to identify in rectal/genital tracts because of its ability to cause serious neonatal infections.

Specimen Type


Specimen Requirements

Bacterial Culture Transport Swab w/gel, Amies Transport swab, Eswab. Other transport systems also accepted.

Specimen Collection / Processing Instructions

Obtain a swab of the distal vagina and anorectum between 35-37 weeks gestation.


Ambient: 48 hours

Unacceptable Specimen Conditions

Frozen, delayed greater than 48 hours in transport


A positive culture indicates colonization with Group B Streptococcus, which may or may not indicate infection.

Department (code)




Estimated TAT

2-4 days

Testing Schedule


Test Includes


CPT Code(s)

87070, 87186

Reflex Conditions

Reflex to susceptibilty if positive for GBS.

Performing Lab

Incyte Diagnostics

LOINC Code(s)

72607-5, 193-3

Additional Information

Colonization of the maternal tract is associated with colonization of infants and a risk of neonatal infections characterized by pneumonia, sepsis, and possible meningitis. GBS is also associated with postpartum infections in the mother. The CDC recommends screening of all pregnant women between 35 and 37 weeks gestation for the presence of GBS through the collection of a cervical, perianal, perirectal, or perineal specimen.