Table 4.

Results of Xpert C. difficile 027/NAP1/BI test compared to results of standard typing methods

ParameteraNo. of isolates of the indicated type/no. of isolates tested (%)bP valuec
PCR ribotype 027 (n = 350)PFGE type NAP1 (n = 342)REA type BI (n = 330)
Sensitivity91/92 (98.9)88/91 (96.7)85/88 (96.6)0.5739
Specificity253/258 (98.1)244/251(97.2)236/242 (97.5)0.8343
PPV91/96 (94.8)88/95 (92.6)85/91 (93.4)0.8287
NPV253/254 (99.6%)244/247 (98.8)236/239 (98.7)0.5779
  • a PPV, positive predictive value; NPV, negative predictive value.

  • b Typing was determined by the indicated method. The denominator changes because not all isolates were available for typing by each method. n, total number of isolates.

  • c Calculated using Fisher's exact test.