Accuracy of a rapid intrapartum group B Streptococcus test: A new immunochromatographic assay.

Objectives: To decrease the incidence of early-onset group B streptococcal (GBS) disease, a culture-based screening of all pregnant women at 35-37 weeks is recommended. This gold standard test requires 24-72hours culture. This delay precludes its use for intrapartum screening. This study assesses a new immunoassay, the DIMA test, for identifying GBS-positive patients in the labor ward.

Materials And Methods: This was a prospective observational study of 195 pregnant women presenting with full-term labor at a single site in France between June and August 2012. We assessed the diagnostic accuracy of intrapartum DIMA testing as compared to intrapartum GBS culture and prenatal screening at 35-38 weeks.

Results: The DIMA test sensitivity and specificity were 57.1% and 83.2%, respectively, as compared to 42.9% and 97% for prenatal culture screening.

Conclusion: The DIMA test assay is a rapid and inexpensive test for the detection of maternal GBS colonization in the labor ward. Its sensitivity is higher than antepartum culture but its specificity is lower. Its performance was inferior to that reported for rapid polymerase chain reaction assays.