Swab the lower vagina (vaginal introitus), followed by the rectum (i.e., insert swab through the anal sphincter) using the same swab or two different swabs. Cultures should be collected in the outpatient setting by the health care provider or the patient, with appropriate instruction. Cervical cultures are not recommended, and a speculum should not be used for culture collection.

Place the swab(s) into a non-nutritive transport medium. Appropriate transport systems (e.g., Amies or Stuart's media without charcoal) are commercially available. If vaginal andrectal swabs were collected separately, both swabs can be placed into the same container. Transport media will maintain group B streptococcus viability for up to four days at room temperature or under refrigeration.

Specimen labels should clearly identify that specimens are for group B streptococcal culture. If susceptibility testing is ordered for penicillin-allergic women, specimen labels also should identify the patient as penicillin-allergic and should specify that susceptibility testing for clindamycin and erythromycin should be performed if group B streptococcus is isolated.