[Re: https://www.hifa.org/dgroups-rss/spotlight-group-b-strep-42-what-every-p... ]
Hi, Neil,
In regards to your post, "This seems to imply that, in a term (40 week) pregnancy, the culture results are 95% to 98% accurate if done between 35 and 40 weeks. We might expect the accuracy of the test to be better at, say, 49 weeks rather than 45 weeks. Or is that not the case?,”
I think you mean 39 weeks rather than 35 weeks, but here’s what one of the sources referenced in the acog.org/gbs <http://acog.org/gbs> guidelines states: "Test performance was similar from 1–5 weeks before delivery, but declined when 6 or more weeks had elapsed between the antenatal culture and delivery.” MARKENSON, G., VENTURA, V., BROWN, L., SCHUCHAT, A., & YANCEY, M. (1996). The Accuracy of Late Antenatal Screening Cultures in Predicting Genital Group B Streptococcal Colonization at Delivery. Obstetrics & Gynecology, 88(5), 811–815.
However, from my GBS parent perspective, having a highly accurate rapid test available that could be performed at the start of labor would be an ideal adjunct scenario for those who test negative (to my understanding, there are several highly accurate rapid tests in development)... or, better yet, a maternal GBS vaccine being available could alleviate the need for testing.
Best,
Marti
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