Laboratory Services

Group B Streptococcus by PCR

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Updated Test Information:

Test Description
Group B Streptococcus by PCR

Beta Group B, Group B strep, GBS, Beta Strep

Test ID


Reflex susceptibility testing for penicillin-allergic patients: add free text to AOE Source or check box on paper requisition

Specimen Type

Vaginal/rectal swab

Specimen Requirements

A vaginal and rectal collection using the preferred eSwab (one or two swab) collection device. Swabs in Amies or liquid Stuart's transport medium are also acceptable. Do not use gel media.

Specimen Collection / Processing Instructions

Using the recommended eSwab or other approved bacterial transport medium, begin by swabbing the lower vagina and the rectum through the anal sphincter. This increases the detection of colonization compared with sampling the cervix or vagina alone according to CDC 2010 recommendations. Replace the swab(s) to the collection device and label the container with the patient's full name and another unique identifier. 


If the patient is allergic to penicillin, please order reflex susceptibility testing on the requisition to confirm the use of an appropriate alternative antibiotic.

Required Information

Complete the Incyte Diagnostics requisition with the patient's demographics and relevant clinical history. Label specimen container with the patient's full first and last name, second unique identifier, and specimen source/site. Note the time of collection.


Room temperature: 24 hours
Refrigerated: 4 days
Frozen (after introduction to Lim broth): 30 days

Unacceptable Specimen Conditions

Unlabeled specimens, specimens in incorrect medium, expired collection devices, specimens subjected to freezing or excessive heat are unacceptable.

Department (code)

Molecular Pathology


Real-time polymerase chain reaction (PCR)

Estimated TAT

12 business days from receipt


Susceptibility testing for positive GBS on penicillin-allergic patients is an additional 2-3 business days

Testing Schedule



Inoculated Lim broth specimen is retained frozen for 30 days

CPT Code(s)

87081 and 87186 - for reflex antibiotic susceptibility testing

Collection File View/Download File