Table 1.

Summary of available tests for Clostridium difficile infection [5, 6, 12]

Test	Sensitivity	Specificity	Substance detected
Toxigenic culture (TC, reference test)	> 95%	80–90%	C. difficile bacteria or spores
Nucleic acid amplification test (NAAT)	92–97%	83–100%	C. difficile nucleic acid (toxin genes)
Glutamate dehydrogenase (GDH)	86–99%	88–100%	C. difficile common enzyme
Toxin A and B enzyme immunoassays (EIA)	51–63%	91–100%	Presence of active toxin production
Glutamate dehydrogenase + toxin A/B immunoassay (GDH + Toxin EIA)	83–100%	91–100%	Suggestive of CDI if compatible signs and symptoms present
Nucleic acid amplification + Toxin immunoassay (NAAT + Toxin EIA)	77–100%	91–100%	Suggestive of CDI if compatible signs and symptoms present