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X37.8 vs X38

X37.8 (Other cataclysmic storms) compared with X38 (Flood), 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 X37.8 lists X38 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named.X37.8 is “Other cataclysmic storms”; X38 is “Flood”.

Registry fact

Can these codes be reported together?

Yes, when both are documented.X37.8 lists X38 under Excludes2: “flood (X38)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

Yes.X37.8’s tabular entry: “flood (X38)”. The note covers X38.

Official ruleGuide: Excludes1 vs Excludes2

Is one a parent or header code?

Both are headers.Both are non-billable headers, and neither contains the other.

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. X38 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

X37.8
Other cataclysmic storms
↔
X38
Flood

What we found

Yes, when both are documented.X37.8 carries an Excludes2 note covering X38: “flood (X38)”

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
X37.8

Other cataclysmic storms

X38

Flood

StatusDiffers
X37.8
Non-billable header

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

Report instead: X37.8XXA, X37.8XXD, X37.8XXS

X38
Non-billable header

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

Report instead: X38.XXXA, X38.XXXD, X38.XXXS

Excludes1Differs
X37.8

None at this code

X38
  • collapse of dam or man-made structure causing earth movement (X36.0)
  • tidal wave NOS (X37.41)
  • tidal wave caused by storm (X37.42)
Excludes2Differs
X37.8
  • flood (X38)
X38

None at this code

CategoryDiffers
X37.8

X37 Cataclysmic storm

X38

Is itself a category

ChapterSame for both

V00-Y99 — External Causes of Morbidity (V00-Y99)

IncludesDiffers
X37.8
  • Cloudburst
  • Torrential rain
X38
  • Flood arising from remote storm
  • Flood of cataclysmic nature arising from melting snow
  • Flood resulting directly from storm
7th characterDiffers
X37.8
  • The appropriate 7th character is to be added to each code from category X37
X38
  • The appropriate 7th character is to be added to code X38

No Code first, Use additional code and Code also 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