Diagnosis and Assessment
Î Stool culture is the most sensitive test and is essential for epidemiological studies (A-II).
Î Testing for C. difficile or its toxins should be performed only on diarrheal (unformed) stool unless ileus due to C. difficile is suspected (B-II).
Î Testing of stools of asymptomatic patients, including use as a test of cure, is not recommended except for epidemiological studies (B-III).
Î Enzyme Immuno-Assay (EIA) testing for toxin A and B is rapid but is less sensitive than the cell cytotoxin assay and is thus a sub-optimal alternative approach for diagnosis (B-II).
> Comment: One potential strategy to overcome this problem is a two-step method using EIA for glutamate dehydrogenase (GDH) as an initial screen and the cell cytotoxicity assay or toxigenic culture as the confirmatory test only on GDH positive stools. This approach remains an interim recommendation (B-II).
Î Polymerase chain reaction (PCR) testing appears to be rapid, sensitive and specific and may ultimately address testing concerns. More data on utility are necessary before this methodology can be recommended for routine testing (B-II).
Î Repeat testing during the same episode of diarrhea is of limited value and should be discouraged (B-II).
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