Spotlight: Group B Strep (34) The limitations of screening (3)

11 July, 2026

[Re: https://www.hifa.org/dgroups-rss/spotlight-group-b-strep-25-question-mar... ]

Hi, I just want to follow up on the specimen collection topic mentioned in my previous response to Kelli and how that might impact a mom’s GBS status.

In looking at the American Society for Microbiology’s Guidelines for the Detection and Identification of Group B Streptococcus (which can be downloaded at https://asm.org/guideline/guidelines-for-the-detection-and-identificatio...), their recommendations under Specimen, Storage, Collection and Transport are:

- Use a single swab to obtain a screening specimen first from the lower vagina and then from the rectum without use of a speculum.

- Collect vaginal-rectal specimens using a flocked swab and place in a liquid-based transport medium such as Amies transport media.

- Transport vaginal-rectal specimens to the testing laboratory within 24 hours.

There is detailed info as to why flocked swabs are preferable to traditional fiber wrapped swabs and what to if a specimen culture is delayed beyond 24 hours after collection as that may yield false negatives.

Best,
Marti

(Ms.) Marti Perhach
CEO/Cofounder
Group B Strep International
+1 909 620-7214
marti.perhach@gbs-intl.org <mailto:marti.perhach@gbs-intl.org>
www.groupbstrepinternational.org

CHIFA profile: Marti Perhach is CEO/Cofounder of Group B Strep International, United States. Professional interests: Group B strep disease research and prevention, prenatal infection, One Health. www.groupbstrepinternational.org Email address: marti.perhach AT gbs-intl.org

Author: 
Marti Perhach, United States