Table 2.

Characteristics of sensitivity and specificity of real-time PCR compared with culture method (as the gold standard) for detection of GBS in 200 recto-vaginal swab specimens

Real-time PCR Culture	Positive	Negative
Positive	16	6
Negative	7	171
Sensitivity	72.7%
95% CI	64 - 81.4%
Specificity	96.1%
95% CI	92.4 - 99.8%
PPV*	69.6%
95% CI	63.2 -76%
NPV *	96.6%
95% CI	93.1- 99.9%
False positive	3.9%
False negative	27.3%

^*PPV, positive predictive value; NPV, negative predictive value.