Indicated for:
Profuse watery<unk>  with signs of hypovolemia
Severe abdominal pain
Fever >38.5 (101.3) (suggests infection with invasive bacteria)
Symptoms >2-3d
Blood or pus in stool (E. coli 0157:H7)
Recent hospitalization or antibiotic use
Elderly or immunocompromised
Systemic illness with<unk>  (esp if pregnant (listeria))
Used to differentiate invasive from noninvasive infectious<unk> s
Sn 50-80%, Sp 83% for presence of bacterial pathogen
If patient has +leukocytes but negative infection consider IBD
Plays minor role in ED evaluation
Yield is only 1.5-5.5%
Consider in patients with
Immunosuppression
Severe, inflammatory<unk>  (including bloody<unk> 
Underlying IBD (need to distinguish between flare and superimposed infection)
Immunosuppression
Severe, inflammatory<unk>  (including bloody<unk> 
Underlying IBD (need to distinguish between flare and superimposed infection)
Indicated if parasitic cause is suspected:<unk>  >7d
Untreated water
AIDS
Bloody<unk>  with few or no fecal leukocytes (intestinal amebiasis)<unk>  >7d
Untreated water
AIDS
Bloody<unk>  with few or no fecal leukocytes (intestinal amebiasis)
10% false negative rate
Turnaround time for results varies by institution
Warranted in severely dehydrated patients
Consider if<unk>  + cough (Legionella)
Consider abdominal CT if abdominal tenderness or suspicion of surgical abdomen (e.g. appendicitis, small bowel obstruction, mesenteric ischemia)
Abdominal X-ray is almost never indicated given low sensitivity for pathology (e.g. obstruction)
Acute diarrhea
Viral 
Acute gastroenteritis 
Bacterial
Acute gastroenteritis
Campylobacter
Acute fever
Shigella