Diagnosis largely based on clinical presentation + epidemiological risk factors
Fecal smears will NOT show leukocytes or erythrocytes.
Diagnosis can be confirmed by stool cultures on TCBS medium (must inform lab<unk>  is suspected so appropriate medium is used)
Labs; non-specific abnormalities:
hyponatremia
hypokalemia
hypoglycemia
hemoconcentration (increased hematocrit & plasma protein concentration) from water depletion)
hyponatremia
hypokalemia
hypoglycemia
hemoconcentration (increased hematocrit & plasma protein concentration) from water depletion)
Cholera
Viral 
Traveler's diarrhea
Bacterial
Malaria
Campylobacter
Schistosomiasis
Shigella