C. diff toxin assay
Sn 63-94%, Sp 75-100%
Culture
Positive culture only means C. diff present, not necessarily that it is causing disease
Sn 63-94%, Sp 75-100%
Positive culture only means C. diff present, not necessarily that it is causing disease
For patients with suspected<unk> associated diarrhea (CDAD)
Low suspicion
Send stool for C. diff toxin assay
Positive → treat (no further testing indicated)
Negative → do not treat (no further testing indicated)
High suspicion
Send stool for C. diff toxin assay AND treat empirically
Positive → treat (no further testing indicated)
Negative → Consider discussion with ID (false negative tests may occur); eval for other causes of diarrhea
Send stool for C. diff toxin assay
Positive → treat (no further testing indicated)
Negative → do not treat (no further testing indicated)
Positive → treat (no further testing indicated)
Negative → do not treat (no further testing indicated)
Send stool for C. diff toxin assay AND treat empirically
Positive → treat (no further testing indicated)
Negative → Consider discussion with ID (false negative tests may occur); eval for other causes of diarrhea
Positive → treat (no further testing indicated)
Negative → Consider discussion with ID (false negative tests may occur); eval for other causes of diarrhea
Never a need for repeat testing within 7 days of a previous test
NO NEED to repeat positive tests as symptoms resolve as a “test of cure”
NO NEED to repeat test soon after initial negative test (more likely to be a false positive test than a true positive test)
Testing in infants < 1 year of age not recommended due to high rates of colonization
~40% of infants < 1 month are colonized and asymptomatic
~15% in infants 6-12 months
By 2 years of age, normal flora is established, similar to adults
~40% of infants < 1 month are colonized and asymptomatic
~15% in infants 6-12 months
By 2 years of age, normal flora is established, similar to adults
Clostridium difficile 
Viral 
Salmonella
Bacterial
Campylobacter jejuni
Campylobacter
Yersinia enterocolitica
Shigella