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K51.418 ICD-10-CM Code: Inflammatory polyps of colon with other complication

K51.418 maps to CMS-HCC V28 81. A source-labeled RAF reference is available. Documentation must support MEAT. MEAT criteria · RAF Calculator · free HCC coding tools

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FY 2026 Apr update / Diseases of the digestive system (K00-K95) / Noninfective enteritis and colitis (K50-K52)

K51.418

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Inflammatory polyps of colon with other complication

Growths in the colon caused by inflammation with a complication other than bleeding, obstruction, fistula, or abscess.

Buddy the Bee presenting code insight

Buddy Insight

Inflammatory polyps of the colon with other complication captures complications beyond bleeding, obstruction, fistula, and abscess that accompany pseudopolyps in ulcerative colitis.

CMS-HCC V28

HCC 81

Code-level coefficient reference

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 048

Code-level coefficient reference

ESRD/PACE

HCC 35

Code-level coefficient reference

RXHCC

HCC 67

Code-level coefficient reference

Code Book Path

Official
K51.4Inflammatory polyps of colon
K51.41Inflammatory polyps of colon with complications
K51.418Inflammatory polyps of colon with other complication

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for K51.418 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for K51.418 in this effective period.

Related Child Codes

Official
K51.411Inflammatory polyps of colon with rectal bleeding
K51.412Inflammatory polyps of colon with intestinal obstruction
K51.413Inflammatory polyps of colon with fistula
K51.414Inflammatory polyps of colon with abscess
K51.419Inflammatory polyps of colon with unspecified complications

Includes

Official

ICD-10-CM does not list Includes notes for K51.418 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for K51.418 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for K51.418 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for K51.418 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for K51.418 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Colonoscopy documenting inflammatory polyps
Clear documentation of the specific complication
Provider statement linking the complication to the inflammatory bowel disease
Treatment plan addressing both the polyps and the complication

MEAT Support

HCC Buddy guidance
Colonoscopy documenting inflammatory polyps
Clear documentation of the specific complication
Provider statement linking the complication to the inflammatory bowel disease
Treatment plan addressing both the polyps and the complication

Audit Caution

HCC Buddy guidance
Using this code when a more specific complication code exists
Not documenting what the 'other' complication is
Confusing 'other' with 'unspecified'
Failing to consider whether the complication warrants additional separate coding

Common Mistakes

HCC Buddy guidance
K51.418 vs K51.411-K51.414 — Use specific codes for bleeding, obstruction, fistula, or abscess
K51.418 vs K51.419 — K51.419 is for unspecified complications; K51.418 is when the complication is identified but non-standard
K51.418 vs K51.40 — K51.40 is without complications

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 K51.418 an HCC code?

Yes. K51.418 (Inflammatory polyps of colon with other complication) maps to HCC 81, Ulcerative Colitis under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 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: K51.418 is billable and maps to V28 HCC 81, Ulcerative Colitis. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
K51.418
Description
Inflammatory polyps of colon with other complication
HCC (V28)
HCC 81 — Ulcerative Colitis
RAF reference coefficient
0.244
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 81, Ulcerative Colitis
0.244
ESRDHCC 35, Inflammatory Bowel Disease
Not separately weighted
RxHCCHCC 67, Inflammatory Bowel Disease
Not separately weighted

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 K51.418 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT Criteria for K51.418

For K51.418 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

  • 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

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed K51.418 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

K51.418 is the ICD-10-CM diagnosis code for inflammatory polyps of colon with other complication. Growths in the colon caused by inflammation with a complication other than bleeding, obstruction, fistula, or abscess. K51.418 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, K51.418 maps to Ulcerative Colitis (HCC 81) with a source-labeled community, non-dual, aged reference coefficient of 0.244. No V24 mapping is shown for K51.418; use the applicable model and payment year when reviewing the V28 mapping. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. 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.

Use this code only when a specific complication is documented but does not fit into the K51.411-K51.414 categories. Because K51.418 maps to an HCC category, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment. 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 K51.418 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Use this code only when a specific complication is documented but does not fit into the K51.411-K51.414 categories
  • •Document the specific complication clearly in the medical record to support medical necessity and justify the use of this code

Clinical Significance

Inflammatory polyps of the colon with other complication captures complications beyond bleeding, obstruction, fistula, and abscess that accompany pseudopolyps in ulcerative colitis. This may include perforation, dysplasia, or extraintestinal manifestations that add complexity to disease management.

Documentation Requirements

  • ✓Colonoscopy documenting inflammatory polyps
  • ✓Clear documentation of the specific complication
  • ✓Provider statement linking the complication to the inflammatory bowel disease
  • ✓Treatment plan addressing both the polyps and the complication
  • ✓Disease activity assessment

Commonly Confused Codes

  • •K51.418 vs K51.411-K51.414: Use specific codes for bleeding, obstruction, fistula, or abscess
  • •K51.418 vs K51.419: K51.419 is for unspecified complications; K51.418 is when the complication is identified but non-standard
  • •K51.418 vs K51.40: K51.40 is without complications

Child Codes

K51.411Inflammatory polyps of colon with rectal bleeding
HCC 81
K51.412Inflammatory polyps of colon with intestinal obstruction
HCC 78
K51.413Inflammatory polyps of colon with fistula
HCC 81
K51.414Inflammatory polyps of colon with abscess
HCC 81
K51.418Inflammatory polyps of colon with other complication
HCC 81
K51.419Inflammatory polyps of colon with unspecified complications
HCC 81

Code Hierarchy

└K51Ulcerative colitis└K51.4Inflammatory polyps of colon└K51.41Inflammatory polyps of colon with complications└K51.418Inflammatory polyps of colon with other complication
└K51.418Inflammatory polyps of colon with other complication

Because K51.418 maps to an HCC category, the documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment.

K51.418 maps to CMS-HCC V28 category 81, Ulcerative Colitis. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for K51.418. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

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Open K51.418 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.

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