ICD-10 Code K59.04 – Chronic idiopathic constipation (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K59.04 – Chronic idiopathic constipation
What it is
K59.04 identifies chronic constipation with no known secondary cause. Use it when the record supports a long-standing functional pattern rather than constipation from medication, obstruction, or another disease.
Clinical signs
Typical findings include infrequent bowel movements, hard stools, straining, or a sense of incomplete evacuation. Clinical features vary; refer to documentation.
When to use this code
Use K59.04 when the provider documents chronic idiopathic constipation, chronic functional constipation, or a similar diagnosis and no cause is identified. It fits outpatient and follow-up notes when the condition is being evaluated or managed over time. Check documentation if the record also suggests another gastrointestinal disorder or drug-induced constipation.
Do not use for
Do not use this code for constipation clearly linked to another condition, such as fecal impaction, bowel obstruction, or medication effect. If the cause is documented elsewhere, code that condition instead.
Coding tip
Confirm that “idiopathic” or an equivalent chronic functional diagnosis is documented before assigning K59.04.