2027 ICD-10-CM Diagnosis Code K51.512Left sided colitis with intestinal obstruction

ICD-10-CM Codes›K00–K95›K50-K52›K51

ICD-10-CM K51.512
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

K51.512 is a billable ICD-10-CM diagnosis code for left sided colitis with intestinal obstruction. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Intestinal obstruction and ileus and Regional enteritis and ulcerative colitis.

For Medicare Advantage risk adjustment, K51.512 maps to CMS-HCC Category 78 (Intestinal Obstruction/Perforation) under the V28 model, adding a risk factor of about 0.326 for a community, non-dual, aged beneficiary in payment year 2027.

Code Identity

ICD-10-CM Code
K51.512
Billable Status
Yes — Valid for Submission
Code Describes
Left sided colitis with intestinal obstruction
Short Description
Left sided colitis with intestinal obstruction
Same as the full description in the CMS dataset.
Parent Code
K51.51
Left sided colitis with complications

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK50-K52Noninfective enteritis and colitis
CategoryK51Ulcerative colitis
This CodeK51.512Left sided colitis with intestinal obstruction

Medicare Risk Adjustment (HCC)Billing

K51.512 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.

CMS-HCC V28 Category (Payment Model)
HCC 78— Intestinal Obstruction/Perforation
Payment HCC · PY 2027 one of 76 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+0.326
community, non-dual, aged · ranges 0.326–0.688 across segments
Hierarchy
Superseded by HCC 77
a more severe related category takes the payment when both are reported
Prior Model (CMS-HCC V24)
HCC 33
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 33 · PACE (CMS-HCC V22): HCC 35 · ESRD (V21): HCC 33 · ESRD (V21): HCC 35 · ESRD (V24): HCC 33 · ESRD (V24): HCC 35
ESRD V21 weights: 0.072 dialysis, 0.285–0.346 functioning graft · ESRD V21 weights: 0.053 dialysis, 0.341–0.362 functioning graft · ESRD V24 weights: 0.078 dialysis, 0.250–0.474 functioning graft · ESRD V24 weights: 0.048 dialysis, 0.286–0.503 functioning graft
Part D (RxHCC)
RxHCC 67 — Inflammatory Bowel Disease
also risk-adjusts in the Part D prescription drug model (V08)

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.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to K51.512: 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.

From Block K50-K52 Noninfective enteritis and colitis applies to 91 codes
  • noninfective inflammatory bowel disease

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From K51 Ulcerative colitis applies to 49 codes
  • Crohn's disease [regional enteritis] (K50.-)
From Block K50-K52 Noninfective enteritis and colitis applies to 91 codes

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.

From Chapter 11 (K00-K95) Diseases of the digestive system applies to 863 codes
  • 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.

From K51 Ulcerative colitis applies to 49 codes
  • code to identify any associated fistulas, if applicable:
  • anal fistula (K60.3-)
  • anorectal fistula (K60.5-)
  • rectal fistula (K60.4-)
  • code to identify manifestations, such as:
  • pyoderma gangrenosum (L88)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name K51.512, its category, or a range that includes it.

Excludes1 3

These codes carry an Excludes1 note naming K51.512: they are not reported together with it, unless the two conditions are unrelated.

  • K50 Crohn's disease [regional enteritis]
    ulcerative colitis (K51.-) names K51.-, which includes this code
  • K62.6 Ulcer of anus and rectum
    ulcerative colitis (K51.-) names K51.-, which includes this code
  • K63.3 Ulcer of intestine
    ulcerative colitis (K51.-) names K51.-, which includes this code

Code First 4

These codes say to code first a condition named in the note, and K51.512 is one of the conditions named.

  • F54 Psychological and behavioral factors associated with disorders or diseases classified elsewhere
    ulcerative colitis (K51.-) names K51.-, which includes this code
  • K60.3 Anal fistula
    ulcerative colitis (K51.-) names K51.-, which includes this code
  • K60.4 Rectal fistula
    ulcerative colitis (K51.-) names K51.-, which includes this code
  • K60.5 Anorectal fistula
    ulcerative colitis (K51.-) names K51.-, which includes this code

Code Also 2

These codes say K51.512 may also be needed to fully describe the condition. The note gives no sequencing direction.

  • M07 Enteropathic arthropathies
    ulcerative colitis (K51.-) names K51.-, which includes this code
  • M08 Juvenile arthritis
    ulcerative colitis (K51.-) names K51.-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR DIG012
Intestinal obstruction and ileus
Default principal diagnosis: inpatient No · outpatient No
CCSR DIG011
Regional enteritis and ulcerative colitis
Default principal diagnosis: inpatient Yes · outpatient Yes

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

Intestinal Obstruction

An intestinal obstruction occurs when food or stool cannot move through the intestines. The obstruction can be complete or partial. There are many causes. The most common are adhesions, hernias, cancers, and certain medicines.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert K51.512 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
556.5 Lftsded ulcertve colitis
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
560.89 Intestinal obstruct NEC
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About K51.512Overview

What is the ICD-10 code for left sided colitis with intestinal obstruction?

The ICD-10-CM code for left sided colitis with intestinal obstruction is K51.512 (sometimes written as K51512). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is K51.512 (Left sided colitis with complications) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report left sided colitis with intestinal obstruction on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does K51.512 group to?

When left sided colitis with intestinal obstruction 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 K51.512 a CC or MCC?

CMS lists K51.512 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 K51.512 be reported with a code from K50?

Not as a rule. The Excludes1 note at K51, which applies to K51.512, 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 K51.512?

K51.512 (left sided colitis with intestinal obstruction) maps to CMS-HCC Category 78 (Intestinal Obstruction/Perforation), commonly written as HCC 78, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 33 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 K51.512 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, K51.512 adds a risk adjustment factor of about 0.326 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.326 to 0.688 depending on the payment segment). A more severe related category (HCC 77) supersedes it when both are reported. See the full factor table on the HCC 78 category page.