Accurate ICD-10-CM coding for gastrointestinal conditions is critical for proper reimbursement, audit compliance, and clinical data integrity. Chronic constipation, though often considered a benign condition, can have significant implications on patient quality of life, healthcare resource utilization, and reimbursement workflows. For coders, the challenge lies in identifying the correct code based on clinical documentation, differentiating subtypes, and applying official coding guidelines to avoid denials or underpayments.
In addition, payers often scrutinize chronic constipation claims for medical necessity especially when tied to high-cost diagnostic procedures or long-term pharmacologic therapy. Coders and CDI specialists must ensure that documentation reflects both the clinical basis for the diagnosis and the chronicity of the condition.
This guide breaks down what chronic constipation is, the correct ICD-10-CM coding approach, related billable codes, documentation standards, and best practices to ensure coding accuracy in both inpatient and outpatient settings.
What is Chronic Constipation?
Chronic constipation is defined as infrequent bowel movements, difficult stool passage, or both, persisting for three months or longer. For ICD-10-CM coding, chronicity should be based on documented symptom duration of ≥3 months, consistent with clinical and coding standards, rather than “several weeks.” It is typically characterized by:
- Infrequent stool frequency fewer than three bowel movements per week.
- Hard, dry stools that are difficult to pass.
- Straining or incomplete evacuation.
- Chronicity duration of symptoms lasting at least three months, often years.
Chronic constipation can be primary (functional/idiopathic) or secondary to conditions such as medication use (e.g., opioids), metabolic disorders (e.g., hypothyroidism), neurologic diseases, or structural abnormalities of the colon or rectum.
From a coding perspective, the chronicity and etiology must be clearly stated to assign the most specific ICD-10-CM code.
What is the ICD-10 Code for Chronic Constipation?
K59.04 – Chronic idiopathic constipation
This code is assigned when documentation indicates a chronic, ongoing condition without an identifiable secondary cause. According to the ICD-10-CM Official Guidelines for Coding and Reporting (FY 2025), coders should assign the most specific constipation code supported by provider documentation of type, chronicity, and etiology (e.g., K59.04 for chronic idiopathic constipation). Also, always review inclusion and exclusion notes in the Alphabetic Index and Tabular List to confirm correct code selection.
Compliance note: Coders should never assume chronicity or idiopathic status based on symptom history alone. The provider must explicitly document these terms, or a query should be initiated.
When to Use and When Not to Use K59.04
When to Use:
- Documentation explicitly states “chronic idiopathic constipation” or “functional constipation.”
- Symptoms have persisted for at least three months and meet the chronic definition.
- No secondary cause is identified after evaluation.
- The provider’s note links the constipation to a primary functional cause rather than a transient condition.
When Not to Use:
- The constipation is acute or short-term (use K59.00 or other appropriate acute code).
- The constipation is clearly secondary to another condition (e.g., drug-induced, outlet dysfunction, slow transit).
- There is an underlying diagnosis (e.g., fecal impaction, bowel obstruction) that takes precedence for coding.
- Documentation uses nonspecific language like “patient complains of constipation” without specifying type or duration.
Sequencing Note: When constipation is secondary to another condition (e.g., hypothyroidism, Parkinson’s disease, opioid use), code the underlying cause first, followed by the appropriate constipation code (e.g., K59.03 for drug-induced constipation). This sequencing follows ICD-10-CM guidelines to ensure accurate reporting of the primary condition driving the patient’s care.
Related ICD-10 Codes for Constipation
| Code | Description | Common Use Case |
|---|---|---|
| K59.00 | Constipation, unspecified | Constipation documented without type or chronicity |
| K59.01 | Slow transit constipation | Confirmed colonic motility disorder with delayed stool passage |
| K59.02 | Outlet dysfunction constipation | Pelvic floor dysfunction or dyssynergic defecation |
| K59.03 | Drug-induced constipation | Medication-related cases (e.g., opioids, anticholinergics) |
| K59.04 | Chronic idiopathic constipation | Long-term functional constipation without secondary cause |
| K59.09 | Other constipation | Atypical constipation not covered by other subcategories |
| K56.41 | Fecal impaction | Severe stool retention requiring intervention |
| R15.0 | Incomplete defecation | Persistent sensation of incomplete evacuation |
Why This Helps Coders
- Inclusion terms come directly from the official ICD-10-CM Tabular List, so they are authoritative.
- It speeds up code selection because coders can match provider language directly to code options.
- It helps reduce unspecified code overuse, because coders can identify a more specific match without extra queries.
Documentation Requirements
Accurate coding depends entirely on provider documentation. To code chronic constipation correctly, the record should include the following elements: (these bullet points are NOT new headings, keep the format same)
- Type of constipation: Specify whether the case is idiopathic, slow transit, outlet dysfunction, drug-induced, or unspecified.
- Chronicity: Document the duration of symptoms and confirm that it meets the clinical definition of chronic constipation.
- Etiology: For idiopathic cases, confirm that no secondary causes have been identified through patient history and examination.
- Diagnostic evidence: Include results from relevant testing such as colon transit studies, anorectal manometry, or Sitzmarker testing, if performed.
- Linkage to underlying causes: When drug-induced constipation is suspected, link the diagnosis to the patient’s medication list to establish causality.
- Severity and impact: Describe the degree of symptom severity and its effect on daily activities to justify medical necessity for treatments or procedures.
Clinical Validation Reminder: Always ensure that the provider’s documentation of constipation including type, chronicity, and etiology is supported by the patient’s clinical presentation and objective findings (e.g., physical exam notes, diagnostic test results, symptom duration). Coding a diagnosis without sufficient clinical correlation can lead to audit findings, claim denials, or compliance risks.
Best Practices for Accurate Coding
1- Educate Providers on Specificity Needs
Encourage precise terminology in notes: “Chronic idiopathic constipation” rather than simply “constipation.”
2- Query When Documentation is Incomplete
If chronicity or type is not specified, submit a coding query before defaulting to unspecified codes.
3- Differentiate from Complications
Separate codes should be assigned if complications like fecal impaction or incomplete defecation are documented.
4- Follow Excludes1 and Excludes2 Rules
Be aware of codes that cannot be reported together for the same encounter unless separately justified.
5- Audit for Overuse of Unspecified Codes
Audit constipation coding regularly to detect and correct overuse of unspecified codes.
Precision Coding Support for Chronic Constipation Cases
Our Pro-MBS team understands that coding gastrointestinal conditions such as chronic constipation requires more than a basic ICD-10-CM lookup. We combine advanced coding expertise with clinical documentation improvement (CDI) strategies to ensure claims are complete, compliant, and fully defensible during audits. This process includes targeted provider education on documenting type, duration, and etiology, along with meticulous pre-submission audits designed to capture missed specificity and correct coding variances before claim submission.
Through real-time coder–provider collaboration and structured denial-prevention workflows for high-scrutiny gastrointestinal diagnoses, our team ensures accurate code assignment that aligns with payer guidelines and industry standards. These measures not only safeguard reimbursement but also strengthen compliance posture, reduce denial rates, and support the long-term financial stability of healthcare organizations.
