If profuse diarrhea or clinical dehydration, check electrolytes, CBC
Consider stool studies if:
Signs of hypovolemia
Fever >38.5
Blood or pus in diarrhea
Symptoms >2-3 days
Elderly, immunocompromised, or recent hospitalization
Consider abdominal CT if concern for other critical intrabdominal pathology
Signs of hypovolemia
Fever >38.5
Blood or pus in diarrhea
Symptoms >2-3 days
Elderly, immunocompromised, or recent hospitalization
Clostridium perfringens
Viral 
Bacillus cereus
Bacterial
Bacteroides fragilis
Campylobacter
Clostridium sordellii
Shigella