Stool Osmotic Gap Calculator
Use stool sodium and potassium concentrations to estimate whether chronic diarrhea is more likely osmotic, secretory, or indeterminate in pattern.
Result
Stool Osmotic Gap:
Stool Osmotic Gap = 290 − 2 × (Stool Na+ + Stool K+)- < 50 mOsm/kg: suggests secretory diarrhea
- 50–100 mOsm/kg: indeterminate / mixed pattern
- > 100 mOsm/kg: suggests osmotic diarrhea
This calculator is for educational and clinical support purposes only. Results should be interpreted with the patient’s history, examination, medication use, diet, stool collection quality, and other investigations.
