Rapid intrapartum PCR assay for group B streptococcus within a dutch risk-based strategy: diagnostic accuracy and...

To compare the diagnostic accuracy of a rapid intrapartum polymerase chain reaction (PCR) assay with standard intrapartum culture for detecting maternal group B streptococcus (GBS) carriage, and to explore potential effects on intrapartum antibiotic prophylaxis (IAP) within a Dutch risk-based strategy.

GBS is a leading cause of early-onset neonatal sepsis. While many countries apply universal screening, the Netherlands follows a selective, risk-based prevention protocol with markedly lower use of IAP. Standard culture requires 24-48 h, limiting its value in urgent obstetric settings. Rapid intrapartum PCR testing offers results within 1 h and may improve timely decision-making.

Retrospective diagnostic-accuracy cohort.

Secondary care teaching hospital in the Netherlands.

Women who underwent both intrapartum PCR (Xpert Xpress GBS) and culture between 1 February and 30 September 2024 were identified retrospectively through electronic medical and microbiology records. Testing was performed in women with predefined clinical risk factors according to the local Dutch risk-based protocol. The same rectovaginal swab specimen was used for both rapid PCR analysis and standard culture testing.

Diagnostic accuracy of a rapid intrapartum PCR assay was calculated using culture as the reference standard, and expressed primarily as sensitivity and specificity with 95% confidence intervals (CI). PCR and culture results were processed through separate laboratory workflows. Exploratory analyses evaluated IAP administration and test performance across clinical risk factor groups.

A total of 177 women were analysed. The PCR assay showed sensitivity of 94.1% (95% CI 80.3-99.3) and specificity of 99.3% (95% CI 96.2-100.0). Of 33 PCR-positive women, 28 (85%) received IAP; non-treatment was due to rapid labour progression or informed refusal. Exploratory subgroup analyses demonstrated similar findings across prolonged rupture of membranes, preterm birth and other clinical risk factor groups.

Rapid intrapartum PCR testing demonstrated high diagnostic accuracy for GBS detection within a Dutch risk-based prevention protocol. Its integration may support more targeted use of IAP. Prospective multicentre trials are needed to establish clinical impact, cost-effectiveness and neonatal outcomes.