The Definitive Guide to the ICD-9 Code for Constipation

If you’re navigating medical records, billing forms, or historical data, you might find yourself searching for the ICD 9 code for constipation. While the healthcare world has largely transitioned to a newer coding system, understanding ICD-9 codes remains crucial for dealing with older documents or understanding a patient’s long-term history.

This comprehensive guide will not only provide you with the exact code but also place it in its proper context. We’ll explore what the code means, why it was structured the way it was, and how coding has evolved to provide a more precise picture of patient health. Whether you’re a medical professional, a student, a billing specialist, or a patient researching your own records, this article is your essential reference.

Understanding the ICD-9-CM Coding System

Before we dive into the specific code, let’s establish what ICD-9-CM actually is. ICD-9-CM stands for the International Classification of Diseases, 9th Revision, Clinical Modification. It was the official system used in the United States to assign codes to diagnoses and procedures for over three decades, from 1979 until September 30, 2015.

The system served as a universal language for healthcare. It allowed doctors, hospitals, insurers, and researchers to communicate about diseases and conditions consistently. Every possible diagnosis, symptom, and cause of injury had a corresponding code. This standardization was vital for:

• Medical Billing: Insurance companies require a diagnostic code to process claims and determine coverage.

• Tracking Public Health: Agencies like the CDC use coded data to monitor disease outbreaks, track mortality rates, and allocate resources.

• Clinical Research: Researchers rely on coded data to identify patient populations for studies on treatment efficacy and disease patterns.

“ICD-9 was the backbone of healthcare data for a generation. It provided the structure needed to move from paper records to the digital age, even as its limitations became increasingly apparent.” — Healthcare Data Historian

The transition from ICD-9 to ICD-10 on October 1, 2015, was a monumental shift, moving from approximately 14,000 codes to over 70,000. This change was driven by the need for greater specificity and detail in modern medicine.

The Specific ICD-9 Code for Constipation

The core ICD 9 code for constipation is 564.0x.

Let’s break down what this alphanumeric string signifies:

• 564: This is the parent category. In the ICD-9-CM manual, code range 564 represents “Other functional intestinal disorders.” This category includes various conditions where the gut is not working properly, but there is no structural blockage or disease.

• .0: This fourth digit specifies the condition within the 564 category. The “.0” explicitly denotes “Constipation.”

• x (Fifth Digit): This is a placeholder for a required fifth digit subclassifier that provides additional specificity about the type of constipation.

Unlike some ICD-9 codes, “constipation” required this fifth digit for complete coding. This is where the code gets more detailed.

Fifth Digit Specificity for Code 564.0

The fifth digit clarifies the nature of the constipation diagnosis. Here is the complete breakdown:

ICD-9-CM Code 564.0x: Constipation

Important Note for Readers: If you are dealing with a medical record or bill dated October 1, 2015, or later, the provider should have used an ICD-10-CM code. The use of ICD-9 codes for current services is incorrect and will cause claim denials. The information here is primarily for historical reference or understanding old records.

Clinical Context and Related ICD-9 Codes

Constipation is rarely an isolated data point. In ICD-9, it was often linked to other codes to paint a fuller clinical picture. Understanding these related codes helps in accurately interpreting historical records.

Common Concomitant Codes

Providers often billed these codes alongside 564.0x to indicate related conditions or causes:

• 787.91 – Diarrhea: Paradoxically, some patients with chronic constipation (especially overflow incontinence) may present with diarrhea.

• 789.0x – Abdominal pain: Abdominal discomfort or pain is a frequent symptom of constipation.

• 536.2 – Persistent vomiting: In severe cases like bowel obstructions (related to or caused by constipation).

• 560.39 – Other impaction of intestine: For severe, chronic constipation leading to fecal impaction.

• Codes for Underlying Causes: Such as 250.6x (Diabetes with neurological manifestations, which can cause gastroparesis/constipation), 244.9 (Unspecified hypothyroidism), or codes for electrolyte imbalances.

The Importance of Etiology

A key principle in medical coding is to code the cause if it is known. In the ICD-9 system, if constipation was documented as being caused by a drug or another condition, coding rules often required listing the underlying cause first.

Example: A patient with constipation due to opioid pain medication following surgery might have had the following codes:

1. 338.18 – Other acute post-traumatic pain (if the post-surgical pain was being treated).

2. E935.2 – Opioids causing adverse effects in therapeutic use (an external cause code from the E-code supplement).

3. 564.00 – Unspecified constipation.

This sequencing tells the full story: the pain led to opioid use, which in turn caused constipation.

The Transition to ICD-10-CM: From 564.0 to K59.0

The shift to ICD-10-CM on October 1, 2015, marked a significant evolution in how constipation is classified. The old code 564.0x was replaced by codes in the K59.0- category.

The move to ICD-10 was driven by the need for greater clinical detail. Where ICD-9 had one category with four subtypes, ICD-10 offers a more nuanced classification that better reflects modern medical understanding.

ICD-9 vs. ICD-10: A Comparative Table for Constipation

Why Specificity Matters: The ICD-10 Advantage

The newer codes provide immediate, actionable data. For instance:

• K59.03 – Drug induced constipation eliminates the need for an additional external cause code in many cases.

• K59.04 – Chronic constipation immediately informs the payer that this is a long-term condition, potentially affecting management and coverage.

• This specificity improves patient care coordination, quality tracking, and the accuracy of public health data.

Practical Application: How the Code Was Used

To truly understand the ICD 9 code for constipation, it helps to see it in action within the healthcare workflow that existed before 2015.

In Medical Billing and Insurance Claims

The process followed these general steps:

1. Patient Encounter: A patient presents with symptoms of constipation.

2. Provider Documentation: The physician documents the diagnosis in the patient’s chart, e.g., “Chronic slow-transit constipation.”

3. Coding: A medical coder (or the provider) reviews the chart and translates the diagnosis into the appropriate ICD-9 code: 564.01.

4. Claim Submission: The code 564.01 is placed on the CMS-1500 (professional) or UB-04 (hospital) claim form, alongside codes for any services performed (like an office visit, 99213).

5. Adjudication: The insurance payer reviews the claim. The ICD-9 code 564.01 justifies the medical necessity of the visit and any related tests or treatments.

In Medical Records and Charting

Within a patient’s SOAP note (Subjective, Objective, Assessment, Plan), the code would appear:

• Assessment: “1. Constipation, slow-transit type. (ICD-9 564.01)”
  This allowed for quick scanning and standardized data extraction for quality reviews or hospital indexing.

Common Points of Confusion and Clarification

Even for experienced professionals, certain aspects of coding for constipation could be confusing. Let’s clarify some frequent questions.

Constipation vs. Other Digestive Issues

• Irritable Bowel Syndrome (IBS): IBS with constipation (IBS-C) had its own distinct code: 564.1. This was crucial, as IBS is a specific functional disorder with a different treatment pathway than general constipation.

• Encopresis: This is fecal incontinence in children, often related to chronic constipation and overflow. It was coded under 787.6, not 564.0.

• Fecal Impaction: This is a severe complication, coded as 560.39. While caused by constipation, it represents a more acute, serious condition.

The Role of “Unspecified” Codes

Code 564.00 (Unspecified constipation) was one of the most commonly used codes, but it was often seen as a last resort. Coders were instructed to always seek a more specific diagnosis from the provider’s documentation. However, in busy clinical settings, if the documentation simply stated “constipation,” 564.00 was the correct and necessary choice.

The Legacy and Importance of Accurate Historical Coding

Why does this matter today? You might be researching an old medical bill, reviewing a family member’s lengthy health history, or working with datasets that span the ICD-9/ICD-10 transition.

• Continuity of Care: A patient’s history of chronic constipation (564.01) informs their current care under ICD-10 (likely K59.04 or K59.01).

• Legal and Disability Records: Historical claims for conditions like chronic constipation may be relevant for long-term disability or legal cases.

• Research: Longitudinal studies on gastrointestinal disorders rely on accurate translation between coding systems to track trends over decades.

Understanding that 564.0x translates to a family of constipation diagnoses helps you accurately interpret these historical documents. It was not just a number; it was a specific clinical concept within the framework of its time.

Conclusion

The search for the ICD 9 code for constipation leads to the specific family of codes 564.0x, with the fifth digit providing essential detail on the type, such as slow transit or outlet dysfunction. While this system was retired in 2015, its codes are key to unlocking decades of medical history and data. The transition to ICD-10-CM, with codes like K59.00, reflects medicine’s ongoing pursuit of greater precision to enhance patient care, streamline billing, and improve public health insights.

Frequently Asked Questions (FAQ)

Q: Can I still use ICD-9 code 564.0 for a medical claim today?
A: No. As of October 1, 2015, all healthcare providers covered by the HIPAA mandate must use ICD-10-CM codes for diagnosis reporting. Using an ICD-9 code will result in immediate claim rejection.

Q: I have an old bill with code 564.00. What does that mean for my health?
A: It simply indicates you were diagnosed with unspecified constipation at that time. For current health concerns, consult your current medical records which will use ICD-10 codes. It’s a piece of your health history, not an active diagnosis.

Q: Is there a direct one-to-one match between ICD-9 code 564.01 and an ICD-10 code?
A: Very nearly. ICD-9 564.01 (Slow transit constipation) maps most directly to ICD-10 K59.01 (Slow transit constipation). The clinical meaning is identical; only the code changed.

Q: Why was the coding system changed? Wasn’t ICD-9 good enough?
A: ICD-9 was running out of space for new diagnoses and lacked the detail needed for modern medicine, value-based care, and precise public health tracking. ICD-10’s specificity reduces ambiguity, leading to fewer coding errors and clearer communication.

Q: Where can I find an official, current list of ICD-10 codes?
A: The authoritative source is the Centers for Medicare & Medicaid Services (CMS) or the National Center for Health Statistics (NCHS). You can access the complete ICD-10-CM files on the CMS website.

Additional Resource

For the official 2026 ICD-10-CM code set and guidelines, please visit the Centers for Disease Control and Prevention (CDC) ICD-10-CM page. This is the primary source for current coding information in the United States.

Disclaimer: This article is for informational and educational purposes only. It is intended to explain historical medical coding concepts. It does not constitute medical or coding advice. For diagnosis and treatment of any medical condition, including constipation, consult a qualified healthcare provider. For official coding guidance and to assign codes for current medical billing, always use the most current ICD-10-CM code set and official guidelines published by the Centers for Medicare & Medicaid Services (CMS) and the National Center for Health Statistics (NCHS). The author and publisher are not responsible for any errors in code application or billing decisions made based on this informational content.