Test Performance Summary:
The established performance validation for the Xpect® C Difficile Toxin A/B test demonstrated that the sensitivity and specificity of the test is 86.3% and 96.2%, respectively. The test has a positive predictive value (PPV) of 84.1% and a negative predictive value (NPV) of 96.8%.
A positive test result does not confirm that a CDI is present but only that the presence of toxins A and/or B are in the fecal specimen. Also, the intensity of the positive test line does not correlate with the presence or severity of the infection. The result of the Xpect® test should be used in conjunction with other clinical findings to establish the diagnosis of CDI. In addition, a negative test result does not exclude a CDI or exclude the presence of C diff bacteria. (The toxin level may be below the detection level).