TABLE 2.

Comparison of commercial C. difficile detection assays with results of cytotoxin testing

AssayNo. of samples with the following assay result:Cytotoxin test resultNo. of samples testedSensitivity (%) (95% CI)aSpecificity (%) (95% CI)a
PositiveNegativeEquivocalInvalid
Premier toxin A+B99900Positive10891.7 (84.7-96.1)97.1 (95.1-98.4)
1447400Negative488
GA Clostridium difficile antigen832500Positive10876.8 (67.7-84.4)90.9 (88.0-93.3)
4444400Negative488
Ridascreen toxin A/B723600Positive10866.7 (56.9-75.4)95.1 (92.6-96.7)
2346410Negative488
Techlab toxin A/B II981000Positive10890.7 (83.6-95.5)95.7 (93.4-97.3)
2146700Negative488
Remel ProSpecT971100Positive10889.8 (82.5-94.8)92.6 (89.8-94.7)
3645200Negative488
Vidas C. difficile toxin A/B97290Positive10889.8 (82.5-94.8)96.7 (94.6-98.0)
5472110Negative488
Remel Xpect841770Positive10877.8 (68.8-85.2)98.8 (97.2-99.5)
548210Negative488
Techlab Tox A/B Quik Chek911700Positive10884.3 (76.0-90.6)98.6 (96.9-99.4)
548111Negative488
Premier Immunocard A + B841509Positive10877.8 (68.8-85.2)92.8 (90.1-94.9)
4453031Negative488
Techlab C. diff Chek-6082900Positive9190.1 (81.6-95.1)92.9 (90.1-95.0)
3343400Negative467
BD GeneOhm C. difficile83700Positive9092.2 (84.1-96.6)94.0 (91.3-95.9)
2243606Negative464
  • a The sensitivity and specificity of the assays compared to the gold standard cytotoxin test results are shown. The sensitivity and specificity are given as percentages, and the 95% confidence interval (95% CI) values are shown in parentheses.