K51.519 ICD-10-CM Code: Left sided colitis with unspecified complications
K51.519 maps to CMS-HCC V28 81. A source-labeled RAF reference is available. Documentation must support MEAT. MEAT criteria · RAF Calculator · HCC coding software
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FY 2026 Apr update / Diseases of the digestive system (K00-K95) / Noninfective enteritis and colitis (K50-K52)
K51.519
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceLeft sided colitis with unspecified complications
Inflammation of the left side of the colon with complications that are not specified or detailed in the medical record.
Buddy Insight
Left-sided ulcerative colitis with unspecified complications indicates the provider documented complications but did not specify their nature.
CMS-HCC V28
MappedHCC 81
Code-level coefficient reference
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 048
Code-level coefficient reference
ESRD/PACE
MappedHCC 35
Code-level coefficient reference
RXHCC
MappedHCC 67
Code-level coefficient reference
Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for K51.519 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for K51.519 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for K51.519 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for K51.519 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for K51.519 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for K51.519 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for K51.519 in this effective period.
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 K51.519 an HCC code?
Yes. K51.519 (Left sided colitis with unspecified complications) 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: K51.519 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
- K51.519
- Description
- Left sided colitis with unspecified complications
- HCC (V28)
- HCC 81 — Ulcerative Colitis
- RAF reference coefficient
- 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 K51.519 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT Criteria for K51.519
For K51.519 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 K51.519 during that encounter, not just copy-forwarded from a problem list.
Coder workflow notes
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What This Code Means
K51.519 is the ICD-10-CM diagnosis code for left sided colitis with unspecified complications. Inflammation of the left side of the colon with complications that are not specified or detailed in the medical record. K51.519 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, K51.519 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 K51.519; 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.
This is a less specific code; query the provider if the type of complication can be determined from documentation. Because K51.519 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 K51.519 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a less specific code; query the provider if the type of complication can be determined from documentation
- •Use only when complication is mentioned but the specific type cannot be identified
Clinical Significance
Left-sided ulcerative colitis with unspecified complications indicates the provider documented complications but did not specify their nature. This code should prompt a provider query to determine the specific complication type, improving clinical data accuracy and risk adjustment precision.
Documentation Requirements
- ✓Confirmed left-sided ulcerative colitis diagnosis
- ✓Provider acknowledgment that complications exist
- ✓Documentation of provider query attempt to clarify complication type
- ✓Treatment plan addressing the colitis and associated complications
- ✓Disease activity and severity assessment