Functional diarrhea

This code represents chronic diarrhea without an identifiable organic cause, such as infection, inflammation, or malabsorption. It is characterized by recurrent loose or watery stools, often associated with urgency and abdominal discomfort, but not meeting criteria for irritable bowel syndrome. The diagnosis is typically made after excluding other potential etiologies.

Use this code when documentation explicitly states "functional diarrhea" following a thorough diagnostic workup that rules out infectious, inflammatory, and structural causes. This diagnosis is often made by gastroenterologists after negative stool studies, colonoscopy, and imaging. It applies to patients experiencing chronic diarrheal symptoms that do not fit other specific diagnoses.

• Ensure documentation clearly distinguishes functional diarrhea from diarrhea due to irritable bowel syndrome (IBS-D), as these are Excludes1.
• Do not use this code for acute or unspecified diarrhea; refer to R19.7 for those scenarios.
• Look for provider notes indicating a diagnosis of exclusion after appropriate investigations.