Evaluation of a rapid screening test for detecting group B streptococci in pregnant women.

The QUIDEL Group B Strep Test is an enzyme immunoassay (EIA) that was compared with culture for the rapid detection of moderate to high levels of group B streptococci (GBS) colonization in pregnant women. A total of 331 pregnant women were included in the study protocol, and GBS were cultured from 19 of these patients in moderate or greater amounts (incidence of 5.7%). Compared with culture, the EIA had a sensitivity, specificity, and positive and negative predictive values of 89, 99, 89, and 99%, respectively. With a sensitivity of 89%, the 95% confidence interval for this assay is 88 to 90%. The QUIDEL EIA test can be performed in less than 10 min and appears to be a reliable method for detecting moderate or greater amounts of GBS in vaginal or cervical specimens.