TABLE 1

Sensitivity and Specificity of direct ESwab PCR and Lim broth PCR with the BD Max GBS assaya

ComparisonESwab PCR, %Lim broth PCR, %ESwab PCR vs Lim broth PCR, %McNemar test
Estimate95% CIbEstimate95% CIDifference95% CI
Sensitivityc
    Same-day ESwab vs Lim broth PCR92.7 (101/109)86.2–96.299.1 (108/109)95.0–99.8−6.4−12.8 to −1.40.0156
    24-h ESwab vs Lim broth PCR97.2 (106/109)92.2–99.199.1 (108/109)95.0–99.8−1.8−6.7 to 2.20.5000
Specificityd
    Same-day ESwab vs Lim broth PCR96.7 (291/301)94.0–98.295.0 (286/301)91.9–97.01.7−0.1 to 3.80.0625
    24-h ESwab vs Lim broth PCR96.0 (289/301)93.2–97.795.0 (286/301)91.9–97.01.0−0.8 to 3.10.375
  • a Lim broth culture is the reference method.

  • b 95% CI, 95% confidence interval.

  • c Values in parentheses represent the ratio of positive results to true positives.

  • d Values in parentheses represent the ratio of negative results to true negatives.