ICD-10 Code K59.01 – Slow transit constipation (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K59.01 – Slow transit constipation
What it is
K59.01 identifies slow transit constipation, a form of constipation caused by delayed movement of stool through the colon. Use it when documentation specifically supports slow colonic transit rather than constipation in general.
Clinical signs
Typical findings include infrequent bowel movements, hard stools, straining, and a sense of incomplete evacuation. Clinical features vary; refer to documentation, especially if transit delay is confirmed by testing or specialist assessment.
When to use this code
Use K59.01 when the provider documents slow transit constipation, colonic inertia, or delayed colonic transit as the diagnosis. It is appropriate when the record distinguishes this condition from functional constipation, bowel obstruction, or medication-related constipation.
If the chart only says “constipation” without a specific type, check documentation before assigning this code. You should code the documented condition, not assume slow transit based on symptoms alone.
Do not use for
Do not use K59.01 for unspecified constipation, fecal impaction, or constipation clearly due to another cause unless the provider also documents slow transit constipation. Check documentation if the diagnosis is uncertain.
Coding tip
Look for exact wording such as “slow transit” or “colonic inertia” in the assessment or problem list before coding K59.01.