2026 ICD-10-CM Diagnosis Code K51.20Ulcerative (chronic) proctitis without complications
ICD-10-CM Codes›K00–K95›K50-K52›K51
- Billable — Valid for Submission
- Chronic Condition
K51.20 is a billable ICD-10-CM diagnosis code for ulcerative (chronic) proctitis without complications. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 385 through 387. Coders also document this condition as acute proctitis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Regional enteritis and ulcerative colitis.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acute proctitis
- Acute ulcerative proctitis
- Chronic proctocolitis
- Chronic ulcerative proctitis
- Nonspecific ulcerative proctitis
- Proctocolitis
- Ulcerative proctitis
- Ulcerative proctitis in remission
- Ulcerative proctocolitis
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Ulcerative (chronic) proctitis NOS
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- ulcerative (chronic) - K51.20
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Proctitis
- ulcerative (chronic)
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Proctocolitis
inflammation of the rectum and the distal portion of the colon.Ulcerative Proctitis
a form of ulcerative colitis where the inflammation is confined to the rectum.Proctocolitis
inflammation of the rectum and colon.
Patient EducationClinical
Ulcerative Colitis
Ulcerative colitis (UC) is a disease that causes inflammation and sores, called ulcers, in the lining of the rectum and colon. It is one of a group of diseases called inflammatory bowel disease.
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Convert K51.20 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About K51.20Overview
Is K51.20 (Ulcerative (chronic) proctitis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report ulcerative (chronic) proctitis without complications on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does K51.20 group to?
When ulcerative (chronic) proctitis without complications is the principal diagnosis on an inpatient stay, it groups to MS-DRG 385, 386, 387, with relative weights from 0.6813 to 1.5823 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of K51.20?
Under the General Equivalence Mappings, ulcerative (chronic) proctitis without complications converts to ICD-9-CM 556.2 (ulcerative proctitis). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:
- The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
- The condition places limitations on self-care, independent living, and social interactions.
