5
Table 1. Summary of Available Tests for CDI in Decreasing
Order of Sensitivity
Test Sensitivity Specificity
Substance
Detected
Toxigenic culture (TC) High
Low
a
C. difficile vegetative
cells or spores
Nucleic acid
amplification tests
(NAAT)
High Low/moderate C. difficile toxin
genes
Glutamate
dehydrogenase (GDH)
High
Low
a
C. difficile common
antigen
Cell culture cytotoxicity
neutralization assay
(CCNA)
High High Free toxins
Toxin A, B enzyme
immunoassays
Low Moderate Free toxins
a
Must be combined with a toxin test.
