Intrapartum tests for group B streptococcus: accuracy and acceptability of screening

• Published in: BJOG : an international journal of obstetrics and gynaecology 2011-01, Vol.118 (2), p.257-265
• Main Authors: Daniels, JP, Gray, J, Pattison, HM, Gray, R, Hills, RK, Khan, KS
• Format: Article
• Language: English
• Subjects: Accuracy; Adult; Childbirth & labor; Early Diagnosis; Female; Group B streptococcus; Humans; intrapartum prophylactic antibiotics; Medical screening; Parity; Patient Satisfaction; Pregnancy; Pregnancy Complications, Infectious - diagnosis; Prenatal Diagnosis - methods; Rectum - microbiology; Risk Factors; screening; Sensitivity and Specificity; Streptococcal Infections - diagnosis; Streptococcus agalactiae - isolation & purification; Streptococcus infections; Vagina - microbiology; Vaginal Smears
• ISSN: 1470-0328; 1471-0528
• DOI: 10.1111/j.1471-0528.2010.02725.x

Please cite this paper as: Daniels J, Gray J, Pattison H, Gray R, Hills R, Khan K on behalf of the GBS Collaborative Group. Intrapartum tests for group B streptococcus: accuracy and acceptability of screening. BJOG 2011;118:257–265. Objective  To assess the accuracy and acceptability of polymerase chain reaction (PCR) and optical immunoassay (OIA) tests for the detection of maternal group B streptococcus (GBS) colonisation during labour, comparing their performance with the current UK policy of risk factor‐based screening. Design  Diagnostic test accuracy study. Setting and population  Fourteen hundred women in labour at two large UK maternity units provided vaginal and rectal swabs for testing. Methods  The PCR and OIA index tests were compared with the reference standard of selective enriched culture, assessed blind to index tests. Factors influencing neonatal GBS colonisation were assessed using multiple logistic regression, adjusting for antibiotic use. The acceptability of testing to participants was evaluated through a structured questionnaire administered after delivery. Main outcome measures  The sensitivity and specificity of PCR, OIA and risk factor‐based screening. Results  Maternal GBS colonisation was 21% (19–24%) by combined vaginal and rectal swab enriched culture. PCR test of either vaginal or rectal swabs was more sensitive (84% [79–88%] versus 72% [65–77%]) and specific (87% [85–89%] versus 57% [53–60%]) than OIA (P