Evaluation of a rapid enzyme immunoassay test for detection of group B Streptococcus.
The purpose of this study was to determine the reliability of the ICON immunoassay in detecting vaginal group B Streptococcus in pregnant women. Vaginal cultures were obtained at the time of sterile speculum examinations from 300 laboring women. The frequency of vaginal group B streptococcal colonization was 10%. A duplicate vaginal swab was used in the immunoassay, which required less than 10 minutes for completion. The immunoassay could reproducibly detect 3+ to 4+ growth (greater than 10(5) colony-forming units per milliliter of vaginal fluid), which was considered heavy colonization. The overall sensitivity, specificity, positive predictive value, and negative predictive value were 33, 95, 43, and 93%, respectively, compared with culture. For heavy colonization (3+ to 4+ growth), the sensitivity, specificity, positive predictive value, and negative predictive value were 100, 95, 32, and 100%, respectively. The immunoassay is a highly sensitive and specific test for detection of heavy vaginal colonization by group B streptococci in obstetric patients, but cultures are required to detect light group B streptococcal colonization.
Gentry
Y M
YM
Department of Obstetrics and Gynecology, University of Washington, Seattle.
Hillier
S L
SL
Eschenbach
D A
DA
D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D007841:Latex Fixation Tests; D011237:Predictive Value of Tests; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis* / Q000453:epidemiology; D012680:Sensitivity and Specificity; D013290:Streptococcal Infections / Q000175:diagnosis* / Q000453:epidemiology; D013292:Streptococcus agalactiae / Q000302:isolation & purification*; D014621:Vagina / Q000382:microbiology*; D014626:Vaginal Smears