Table 3.

Performance of all assay systems for the detection of CDAD using the final diagnosis based on clinical and laboratory criteria as the gold standard

Assay methodResultSpecimens from patients for whom CDAD status was determined to be (n = 193a):Performance characteristics (%)
Positive (n = 56)Negative (n = 137)SensitivitySpecificityPPVbNPVc
CytotoxinPositive55298999699
Negative1135
ImmunoCard Toxin APositive30254999484
Negative26135
Oxoid Toxin APositive28350989183
Negative28134
TechLab Toxin A/BPositive44379989492
Negative12134
Premier Toxin A&BPositive45380989493
Negative11134
CulturePositive3205710010085
Negative24137
  • a For five patients from whom 7 of 200 specimens were submitted, full clinical details were not accessible. These seven specimens are excluded from the analysis.

  • b PPV, predictive value of a positive result.

  • c NPV, predictive value of a negative result.