Comparison of culture for group B streptococcus versus enzyme immunoassay and latex agglutination rapid tests: results in 250 patients during labor.

Two hundred fifty women in labor were screened for vaginal colonization by group B streptococcus using standard culture and two rapid tests. This primarily Hispanic population had a group B streptococcus vaginal colonization rate of 2.4% (95% confidence interval 0.9-5.2%) for the patients sampled. An enzyme immunoassay and a latex agglutination test for group B streptococcus antigen both had sensitivities of 33% and had specificities of 99 and 95%, respectively, when compared with culture. Neither rapid test appeared to be clinically useful for detecting colonized women in labor, although both can be useful in excluding colonization.