The accuracy of late third-trimester antenatal screening for group B streptococcus in predicting colonization at delivery

Craig Towers, Pamela J. Rumney, Tamerou Asrat, Christine Preslicka, Mark G. Ghamsary, Michael P. Nageotte

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

We reevaluated the accuracy of antenatal group B streptococcal (GBS) culture results in predicting colonization at the time of delivery in a general practice setting. Patients who had late third-trimester antenatal GBS cultures were prospectively identified. A repeat GBS culture was performed when admitted in labor using a strict protocol and laboratory analysis. Sensitivity, specificity, and positive and negative predicative values were calculated. In comparing the office culture results to the intrapartum cultures in 1472 patients, the sensitivity was 51%, specificity 94%, positive predictive value 67%, and negative predictive value 88%. The antenatal positive culture rate of 15.4% was significantly lower than the 20.1% intrapartum positive culture rate. There were 144 patients (9.8%) who had false-negative antenatal culture results. Through office survey, several aspects of the recommended antenatal procedures were not followed. The results support the previously reported high specificity and negative predictive values for this test. The near 10% false-negative rate with the significant difference between the antenatal versus intrapartum positive culture rate highly suggests that late third-trimester culture accuracy may be affected if the specified procedures are not completely followed, including the culturing technique, the use of recommended transport medium, and the laboratory culture protocol.

Original languageEnglish (US)
Pages (from-to)785-789
Number of pages5
JournalAmerican Journal of Perinatology
Volume27
Issue number10
DOIs
StatePublished - Oct 27 2010
Externally publishedYes

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Streptococcus agalactiae
Third Pregnancy Trimester
Prenatal Diagnosis
Predictive Value of Tests
General Practice
Culture Media
Sensitivity and Specificity

All Science Journal Classification (ASJC) codes

  • Pediatrics, Perinatology, and Child Health
  • Obstetrics and Gynecology

Cite this

The accuracy of late third-trimester antenatal screening for group B streptococcus in predicting colonization at delivery. / Towers, Craig; Rumney, Pamela J.; Asrat, Tamerou; Preslicka, Christine; Ghamsary, Mark G.; Nageotte, Michael P.

In: American Journal of Perinatology, Vol. 27, No. 10, 27.10.2010, p. 785-789.

Research output: Contribution to journalArticle

Towers, Craig ; Rumney, Pamela J. ; Asrat, Tamerou ; Preslicka, Christine ; Ghamsary, Mark G. ; Nageotte, Michael P. / The accuracy of late third-trimester antenatal screening for group B streptococcus in predicting colonization at delivery. In: American Journal of Perinatology. 2010 ; Vol. 27, No. 10. pp. 785-789.
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