Eherer AJ, Fordtran JS. Fecal osmotic gap and pH in experimental diarrhea of various causes. Gastroenterology. 1992;103(2):545.

Steffer KJ, Santa Ana CA, Cole JA, Fordtran JS. The practical value of comprehensive stool analysis in detecting the cause of idiopathic chronic diarrhea. Gastroenterol Clin North Am 2012;41:539-560

Castro-Rodriguez JA, Differentiation of osmotic and secretory diarrhoea by stool carbohydrate and osmolar gap measurements.Arch Dis Child. 1997 Sep;77(3):201-5.

Binder HJ, Causes of chronic diarrhea. N Engl J Med. 2006 Jul 20;355(3):236-9.

Duncan A, Robertson C, Russell RI. The fecal osmotic gap: technical aspects regarding its calculation. J Lab Clin Med. 1992 Apr;119(4):359-63.

Schiller L, Sellin J. Diarrhea. In: Sleisenger MH, Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran’s Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis, Management. 9th ed. Philadelphia, Pa.: Saunders/Elsevier; 2010:211-232.

Dr. John S. Fordtran

Stool Osmolar/Osmotic Gap

stool_sodium

stool_potassium

stool_osm

Determines if chronic diarrhea is osmotic or secretory in nature.

Chronic Diarrhea: Osmotic vs Secretory.

John Vizuete, MD, MPH, is currently a senior gastroenterology fellow at the University of Texas Health Science Center at San Antonio. A native Texan, Dr. Vizuete obtained his BA at the University of Texas at Austin, followed by medical school and internal medicine residency training at UTHSCSA. He also holds a master’s degree in public health. Dr. Vizuete is interested in clinical outcomes in gastrointestinal bleeding, luminal endoscopy, and inflammatory bowel disease and is actively involved in medical education.

John Vizuete, MD, MPH

The Stool Osmolar/Osmotic Gap determines if chronic diarrhea is osmotic or secretory in nature.

Stool Osm

Stool Sodium

Stool Potassium

Rome IV for Infant Diarrhea

Kruis Score for IBS

Crohn's Disease Activity Index (CDAI)

The American Academy of Pediatrics (AAP) focuses on the health, safety, and well-being of infants, children, and young adults. With about 67,000 members, including pediatricians, medical subspecialists, and surgical specialists, the AAP supports optimal care. Over 45,000 members are board-certified Fellows of the AAP (FAAP). Its mission is to promote children's health and well-being while supporting members' professional needs.

American Academy of Pediatrics (AAP)

The American Association for Physician Leadership&reg; (AAPL) is the world&rsquo;s oldest and largest professional association dedicated solely to maximizing physician leadership.&nbsp;From the moment physicians begin their leadership journey through the time they are seasoned leaders, AAPL provides education and training, resources and tools, and content and experiences needed to close gaps between hands-on clinical care, organization system improvements and optimized business outcomes.

American Association for Physician Leadership (AAPL)

American Association for the Study of Liver Diseases

The American College of Emergency Physicians (ACEP) represents more than 38,000 emergency physicians, emergency medicine residents and medical students. ACEP promotes the highest quality of emergency care and is the leading advocate for emergency physicians and their patients, and the public. Members may earn up to 850 continuing medical education hours every year through ACEP&rsquo;s robust catalog of peer-reviewed publications and on-demand courses presented by world-renowned emergency medicine experts.

American College Of Emergency Physicians

The American College of Gastroenterology (ACG) supports clinicians in delivering high-quality, evidence-based care to gastroenterology patients. Its mission is to advance care for those with gastrointestinal disorders through excellence, innovation, and advocacy. ACG provides members with up-to-date scientific information through annual meetings, the American Journal of Gastroenterology, training courses, and research grants, focusing on digestive health and GI disorder treatments.

American College of Gastroenterology

American College of Rheumatology

The American Gastroenterological Association (AGA), founded in 1897, provides leadership and education to over 16,000 members worldwide, all dedicated to advancing gastroenterology. The AGA&rsquo;s mission is to empower clinicians and researchers to improve digestive health through clinical guidance, practice resources, and peer-reviewed research. Key journals include Gastroenterology, Clinical Gastroenterology and Hepatology, Cellular and Molecular Gastroenterology and Hepatology, and others.

American Gastroenterological Association

American Heart Association

American Urological Association

EB Medicine is the premier provider of evidence-based clinical content and CME resources for emergency medicine practitioners.

EB Medicine

MDCalc CME

Postgraduate Institute for Medicine

The Rome Foundation is a nonprofit organization dedicated to advancing the diagnosis and treatment of Disorders of Gut-Brain Interaction (DGBI), also known as functional gastrointestinal disorders. Its mission is to improve the lives of people with DGBI. For over 30 years, the Rome Foundation has worked with scientists and clinicians worldwide to classify and assess GI function and dysfunction, creating symptom-based criteria used in clinical trials and daily practice to guide diagnosis and treatment.

The ROME Foundation

Listen to the VACO co-creators break down how to use VACO\, what it does\, and what it doesn’t.

Calc Function

Stool Osmolar/Osmotic Gap