K51.512 ICD-10-CM Code: Left sided colitis with intestinal obstruction
K51.512 maps to CMS-HCC V28 HCCs 78 and 81. Source-labeled RAF references are available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC Buddy coding tools
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FY 2026 Apr update / Diseases of the digestive system (K00-K95) / Noninfective enteritis and colitis (K50-K52)
K51.512
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceLeft sided colitis with intestinal obstruction
Inflammation of the left side of the colon that is blocking the passage of stool through the intestines.
Buddy Insight
Left-sided ulcerative colitis with intestinal obstruction is a serious complication indicating bowel blockage from the inflammatory process in the descending colon.
CMS-HCC V28
MappedHCC 78
Coefficient HCC 78: 0.326 (Community Non-Dual Aged (CNA)); HCC 81: 0.244 (Community Non-Dual Aged (CNA))
+ HCC 81
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 045
Code-level coefficient reference
+ HCC 048
ESRD/PACE
MappedHCC 33
Code-level coefficient reference
+ HCC 35
RXHCC
MappedHCC 67
Code-level coefficient reference
Code Book Path
Inclusion Terms
Official- Left hemicolitisInherited from K51.5
Excludes 2
Official- certain conditions originating in the perinatal period (P04-P96)Inherited from K00-K95
- certain infectious and parasitic diseases (A00-B99)Inherited from K00-K95
- complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from K00-K95
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)Inherited from K00-K95
- endocrine, nutritional and metabolic diseases (E00-E88)Inherited from K00-K95
- injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from K00-K95
- neoplasms (C00-D49)Inherited from K00-K95
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from K00-K95
Related Codes
Includes
Official- noninfective inflammatory bowel diseaseInherited from K50-K52
Excludes 1
Official- irritable bowel syndrome (K58.-)Inherited from K50-K52, K51
- megacolon (K59.3-)Inherited from K50-K52, K51
- Crohn's disease [regional enteritis] (K50.-)Inherited from K50-K52, K51
Code First
OfficialNo Code First sequencing instructions are included in this display for K51.512. Check the code and parent instructions in the Code Book.
Use Additional
Official- code to identify any associated fistulas, if applicable:Inherited from K51
- anal fistula (K60.3-)Inherited from K51
- anorectal fistula (K60.5-)Inherited from K51
- rectal fistula (K60.4-)Inherited from K51
- code to identify manifestations, such as:Inherited from K51
- pyoderma gangrenosum (L88)Inherited from K51
Code Also
OfficialNo Code Also instructions are included in this display for K51.512. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is K51.512 an HCC code?
Yes. K51.512 (Left sided colitis with intestinal obstruction) maps to HCC 78, Intestinal Obstruction/Perforation and HCC 81, Ulcerative Colitis under the CMS-HCC V28 risk adjustment model, with source-labeled community non-dual aged reference coefficients HCC 78 0.326 and HCC 81 0.244. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.
Coder answer: K51.512 is billable and maps to V28 HCC 78, Intestinal Obstruction/Perforation and HCC 81, Ulcerative Colitis. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- K51.512
- Description
- Left sided colitis with intestinal obstruction
- HCC (V28)
- HCC 78 — Intestinal Obstruction/Perforation; HCC 81 — Ulcerative Colitis
- RAF reference coefficient
- HCC 78: 0.326; HCC 81: 0.244
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work K51.512 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for K51.512
For K51.512, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Coder workflow notes
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What This Code Means
K51.512 is the ICD-10-CM diagnosis code for left sided colitis with intestinal obstruction. Inflammation of the left side of the colon that is blocking the passage of stool through the intestines. K51.512 sits in the ICD-10-CM chapter for diseases of the digestive system (k00-k95), within the section covering noninfective enteritis and colitis (k50-k52).
Under the CMS-HCC V28 risk adjustment model, K51.512 maps to Intestinal Obstruction/Perforation (HCC 78) with a source-labeled community, non-dual, aged reference coefficient of 0.326. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.
Intestinal obstruction in colitis is a serious complication that may require hospitalization or surgical intervention. For K51.512, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for K51.512 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Intestinal obstruction in colitis is a serious complication that may require hospitalization or surgical intervention
- •Confirm that the obstruction is secondary to the colitis and not from another cause such as stricture or malignancy
Clinical Significance
Left-sided ulcerative colitis with intestinal obstruction is a serious complication indicating bowel blockage from the inflammatory process in the descending colon. This may result from stricture formation, severe inflammatory edema, or toxic dilation, and typically requires hospitalization with possible surgical intervention.
Documentation Requirements
- ✓Confirmed left-sided ulcerative colitis diagnosis
- ✓Imaging evidence of intestinal obstruction (CT abdomen, abdominal X-ray)
- ✓Documentation of obstruction type (partial vs. complete) and mechanism
- ✓Provider statement linking obstruction to the colitis
- ✓Treatment plan including bowel rest, decompression, or surgical management
- ✓Assessment for toxic megacolon
Commonly Confused Codes
- •K51.512 vs K56.69: K56.69 is other intestinal obstruction unrelated to inflammatory bowel disease
- •K51.512 vs K51.012: K51.012 is pancolitis with obstruction (more extensive disease)
- •K51.512 vs K51.312: K51.312 is rectosigmoiditis with obstruction (more limited)
- •K51.512 vs K91.3x: K91.3x is postprocedural intestinal obstruction; different etiology