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K51.518 ICD-10-CM Code: Left sided colitis with other complication

K51.518 maps to CMS-HCC V28 81 (RAF 0.244). Documentation must support MEAT. MEAT criteria · RAF calculator · HCC Buddy coding tools

ICD-10-CM Code View

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

K51.518

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

Left sided colitis with other complication

Inflammation of the left side of the colon with complications other than bleeding, obstruction, fistula, or abscess.

Buddy the Bee presenting code insight

Buddy Insight

Left-sided ulcerative colitis with other complication captures identified complications beyond the standard categories of bleeding, obstruction, fistula, and abscess.

CMS-HCC V28

HCC 81

RAF 0.244

CMS-HCC V24

HCC 35

RAF 0.308

ACA/HHS

HCC 48

Varies by metal level

ESRD/PACE

HCC 35

RAF 0.048

RXHCC

HCC 67

RAF 0.494

Code Book Path

Official
K51.5Left sided colitis
K51.51Left sided colitis with complications
K51.518Left sided colitis with other complication

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for K51.518 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for K51.518 in this effective period.

Related Child Codes

Official
K51.511Left sided colitis with rectal bleeding
K51.512Left sided colitis with intestinal obstruction
K51.513Left sided colitis with fistula
K51.514Left sided colitis with abscess
K51.519Left sided colitis with unspecified complications

Includes

Official

ICD-10-CM does not list Includes notes for K51.518 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for K51.518 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for K51.518 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for K51.518 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for K51.518 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Confirmed left-sided ulcerative colitis diagnosis
Clear documentation of the specific complication
Provider statement linking the complication to the colitis
Treatment plan for both the colitis and the complication

MEAT Support

HCC Buddy guidance
Confirmed left-sided ulcerative colitis diagnosis
Clear documentation of the specific complication
Provider statement linking the complication to the colitis
Treatment plan for both the colitis and the complication

Audit Caution

HCC Buddy guidance
Using this code when a more specific complication code is available
Not documenting what the 'other' complication is
Confusing 'other' (known, non-standard) with 'unspecified' (unknown)
Not separately coding extraintestinal manifestations that require independent management

Common Mistakes

HCC Buddy guidance
K51.518 vs K51.511-K51.514 — Use specific codes when the complication is bleeding, obstruction, fistula, or abscess
K51.518 vs K51.519 — K51.519 is for unspecified complications; K51.518 is when the complication is identified
K51.518 vs K51.50 — K51.50 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 K51.518 an HCC code?

Yes. K51.518 (Left sided colitis with other complication) maps to Ulcerative Colitis under the CMS-HCC V28 risk adjustment model (and Inflammatory Bowel Disease under V24), with a community non-dual aged RAF of 0.244. It is billable for payment year 2026.

Coder answer: K51.518 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
K51.518
Description
Left sided colitis with other complication
HCC (V28)
HCC 81 — Ulcerative Colitis
RAF
0.244
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 81, Ulcerative Colitis
0.244
V24HCC 35, Inflammatory Bowel Disease
0.308
ESRDHCC 35, Inflammatory Bowel Disease
0.048
RxHCCHCC 67, Inflammatory Bowel Disease
0.494

Each model's RAF is its CMS base weight for that model's standard population, so 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 segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work K51.518 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for K51.518

For K51.518 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 K51.518 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

K51.518 is the ICD-10-CM diagnosis code for left sided colitis with other complication. Inflammation of the left side of the colon with complications other than bleeding, obstruction, fistula, or abscess. K51.518 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, K51.518 maps to Ulcerative Colitis (HCC 81) with a community, non-dual, aged base RAF weight of 0.244. Under the older CMS-HCC V24 model, K51.518 maps to Inflammatory Bowel Disease (HCC 35) with a community, non-dual, aged base RAF weight of 0.308. 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.

Use this code only when a specific complication is documented but doesn't fit K51.511-K51.514. Because K51.518 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. 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, RAF weights, and MEAT documentation criteria for K51.518 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 doesn't fit K51.511-K51.514
  • •Document the specific complication in the medical record for clarity and future reference

Clinical Significance

Left-sided ulcerative colitis with other complication captures identified complications beyond the standard categories of bleeding, obstruction, fistula, and abscess. This includes complications such as toxic megacolon, perforation, primary sclerosing cholangitis, or other extraintestinal manifestations related to the inflammatory bowel disease.

Documentation Requirements

  • ✓Confirmed left-sided ulcerative colitis diagnosis
  • ✓Clear documentation of the specific complication
  • ✓Provider statement linking the complication to the colitis
  • ✓Treatment plan for both the colitis and the complication
  • ✓Disease severity assessment

Commonly Confused Codes

  • •K51.518 vs K51.511-K51.514: Use specific codes when the complication is bleeding, obstruction, fistula, or abscess
  • •K51.518 vs K51.519: K51.519 is for unspecified complications; K51.518 is when the complication is identified
  • •K51.518 vs K51.50: K51.50 is without complications

Child Codes

K51.511Left sided colitis with rectal bleeding
HCC 81
K51.512Left sided colitis with intestinal obstruction
HCC 78
K51.513Left sided colitis with fistula
HCC 81
K51.514Left sided colitis with abscess
HCC 81
K51.518Left sided colitis with other complication
HCC 81
K51.519Left sided colitis with unspecified complications
HCC 81

Code Hierarchy

└K51Ulcerative colitis└K51.5Left sided colitis└K51.51Left sided colitis with complications└K51.518Left sided colitis with other complication
└K51.518Left sided colitis with other complication

Because K51.518 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

K51.518 maps to CMS-HCC V28 category 81, Ulcerative Colitis. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. Because K51.518 carries a payment HCC, you can see what it adds to a RAF score and check the documentation the chart needs before it is submitted.

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Open K51.518 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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