2027 ICD-10-CM Diagnosis Code K51.50Left sided colitis without complications
ICD-10-CM Codes›K00–K95›K50-K52›K51
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 81
- Chronic Condition
K51.50 is a billable ICD-10-CM diagnosis code for left sided colitis without complications. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 385 through 387. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 77 closely related codes. Coders also document this condition as chronic left-sided ulcerative colitis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Regional enteritis and ulcerative colitis.
For Medicare Advantage risk adjustment, K51.50 maps to CMS-HCC Category 81 (Ulcerative Colitis) under the V28 model, adding a risk factor of about 0.244 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
K51.50 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Chronic left-sided ulcerative colitis
- Left sided ulcerative colitis
- Left sided ulcerative colitis in remission
- Ulcerative colitis in remission
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to K51.50: its own notes plus those printed at K51, block K50-K52, and Chapter 11. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- noninfective inflammatory bowel disease
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Left sided colitis NOS
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name K51.50, its category, or a range that includes it.
Excludes1 3
These codes carry an Excludes1 note naming K51.50: they are not reported together with it, unless the two conditions are unrelated.
Code First 4
These codes say to code first a condition named in the note, and K51.50 is one of the conditions named.
- F54 Psychological and behavioral factors associated with disorders or diseases classified elsewhereulcerative colitis (K51.-) names K51.-, which includes this code
- K60.3 Anal fistulaulcerative colitis (K51.-) names K51.-, which includes this code
- K60.4 Rectal fistulaulcerative colitis (K51.-) names K51.-, which includes this code
- K60.5 Anorectal fistulaulcerative colitis (K51.-) names K51.-, which includes this code
Code Also 2
These codes say K51.50 may also be needed to fully describe the condition. The note gives no sequencing direction.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Colitis (acute) (catarrhal) (chronic) (noninfective) (hemorrhagic) See Also: Enteritis; K52.9
left sided K51.50
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Colitis, Ulcerative
inflammation of the colon that is predominantly confined to the mucosa. its major symptoms include diarrhea, rectal bleeding, the passage of mucus, and abdominal pain.
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.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert K51.50 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About K51.50Overview
What is the ICD-10 code for left sided colitis without complications?
The ICD-10-CM code for left sided colitis without complications is K51.50 (sometimes written as K5150). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is K51.50 (Left sided colitis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report left sided colitis without complications on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does K51.50 group to?
When left sided colitis without complications is the principal diagnosis on an inpatient stay, it groups to MS-DRG 385, 386, 387, with relative weights from 0.6462 to 1.5540 depending on complications. Higher weights mean higher Medicare reimbursement.
Is K51.50 a CC or MCC?
CMS lists K51.50 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 77 closely related codes in its exclusion list.
Can K51.50 be reported with a code from K50?
Not as a rule. The Excludes1 note at K51, which applies to K51.50, lists "Crohn's disease [regional enteritis] (K50.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What HCC is K51.50?
K51.50 (left sided colitis without complications) maps to CMS-HCC Category 81 (Ulcerative Colitis), commonly written as HCC 81, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 35 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 67.
Does K51.50 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, K51.50 adds a risk adjustment factor of about 0.244 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.201 to 0.286 depending on the payment segment). A more severe related category (HCC 77 and HCC 80) supersedes it when both are reported. See the full factor table on the HCC 81 category page.
