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K50 vs M04.3

K50 (Crohn's disease [regional enteritis]) compared with M04.3 (VEXAS syndrome), from the official CMS tabular data.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Summary

These codes can be reported together when both conditions are documented, because M04.3 lists K50 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named, billing status and chapter.K50 is “Crohn's disease [regional enteritis]”; M04.3 is “VEXAS syndrome”. K50 is a non-billable header; M04.3 is billable. K50 sits in K00-K95 — Diseases of the Digestive System (K00-K95); M04.3 in M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99).

Registry fact

Can these codes be reported together?

Yes, when both are documented.M04.3 lists K50 under Excludes2: “Crohn's disease (K50.-)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

Yes.M04.3’s tabular entry: “Crohn's disease (K50.-)”. The note covers K50.

Official ruleGuide: Excludes1 vs Excludes2

Is one a parent or header code?

One is a header.K50 is a non-billable header, but M04.3 is not one of its subdivisions.

Registry fact

Nothing found in 3 other checks; 1 check does not apply
Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code. K50 carries 3 Excludes1 notes covering other codes; the side-by-side table quotes them.

Official rule

Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Informational

Excludes2 relationship

M04.3
VEXAS syndrome
↔
K50
Crohn's disease [regional enteritis]

What we found

Yes, when both are documented.M04.3 carries an Excludes2 note covering K50: “Crohn's disease (K50.-)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

What to review

Report both only when the documentation supports both conditions; otherwise report the one documented.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.

Source / rule

CMS ICD-10-CM tabular instructional notes

Official guidance behind these answers

  • Section I.A.12.b — Excludes2 · applies to: Excludes2

    A type 2 Excludes note represents “Not included here.” An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

    ICD-10-CM Official Guidelines FY2027

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

Similar descriptions do not make codes interchangeable. The documentation and the official instructions decide which code applies.

Official descriptionDiffers
K50

Crohn's disease [regional enteritis]

M04.3

VEXAS syndrome

StatusDiffers
K50
Non-billable header

A header is not reported on a claim; a code beneath it is.

Report instead: K50.00, K50.011, K50.012, K50.013, K50.014

M04.3
Billable
Excludes1Differs
K50
  • ulcerative colitis (K51.-)
  • irritable bowel syndrome (K58.-)
  • megacolon (K59.3-)
M04.3

None at this code

Excludes2Differs
K50

None at this code

M04.3
  • Crohn's disease (K50.-)
Use additional codeDiffers
K50
  • 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)
M04.3

None at this code

Code alsoDiffers
K50

None at this code

M04.3
  • any associated conditions
CategoryDiffers
K50

Is itself a category

M04.3

M04 Autoinflammatory syndromes

ChapterDiffers
K50

K00-K95 — Diseases of the Digestive System (K00-K95)

M04.3

M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99)

IncludesDiffers
K50
  • granulomatous enteritis
  • noninfective inflammatory bowel disease
M04.3
  • Vacuoles, E1 ubiquitin-activating enzyme, X-linked, autoinflammatory, somatic syndrome

No Code first and 7th character note at either code.

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on. In a row that differs, each code’s own notes are listed under it, and the notes every code shares are listed once beneath them.

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Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources