Distinction of osmotic from nonosmotic secretory diarrhea. A large deficit (>50 mOsm/kg) in the calculated osmolality (twice the sum of the stool sodium and stool potassium) from the measured stool osmolality indicates osmotic diarrhea.
Stool sample must be collected without addition of water
Screw cap plastic container (sterile)
Ambient - NO
Refrigerated - NO
Freezing point depression