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Test Code CGBS Group B Streptococcus (Streptococcus agalactiae) Culture, Varies

Useful For

Screening for maternal colonization with Streptococcus agalactiae at 36 to 37 weeks gestation as a guide for intrapartum antibiotic prophylaxis to decrease the risk of infection by S agalactiae (group B streptococcus) in the infant

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
RMALD Ident by MALDI-TOF mass spec No, (Bill Only) No
GID Bacteria Identification No, (Bill Only) No
STRP Identification Streptococcus No, (Bill Only) No
ISAE Aerobe Ident by Sequencing No, (Bill Only) No
SIDC Ident Serologic Agglut Method 4 No, (Bill Only) No

Testing Algorithm

When this test is ordered, the reflex tests may be performed and charged.

Reporting Name

Grp B Strep (S. agalactiae) Culture

Specimen Type


Shipping Instructions

Specimen must arrive within 24 hours of collection.

Necessary Information

Specimen source is required.

Specimen Required

Supplies: Culturette (BBL Culture Swab) (T092)

Specimen Type: Swab

Sources: Vaginal/rectal combination swab

Container/Tube: Culture transport swab (Dacron or rayon swab with aluminum or plastic shaft with either Stuart or Amies liquid medium)

Specimen Volume: Swab

Additional Information:

Vaginal/rectal combination swab is the only acceptable specimen according to American College of Obstetricians and Gynecologists (ACOG) guidelines. Vaginal only,  rectal only, as well as other sources are not acceptable.

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Ambient (preferred) 24 hours
  Refrigerated  24 hours

Reference Values


Day(s) Performed

Monday through Sunday

Report Available

3 to 5 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

87081-Strep Grp B (S. agalactiae) culture

87077-Ident by MALDI-TOF mass spec (if appropriate)

87077-Bacteria identification (if appropriate)

87077-Identification Streptococcus (if appropriate)

87147 x 2-6-Serologic Agglut Method 4 Ident (if appropriate)

87153-Aerobe ident by sequencing (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CGBS Grp B Strep (S. agalactiae) Culture 586-8


Result ID Test Result Name Result LOINC Value
CGBS Grp B Strep (S. agalactiae) Culture 586-8

Method Name

Conventional Culture Technique