X35.XXXS vs X37.41

X35.XXXS (Volcanic eruption, sequela) compared with X37.41 (Tidal wave due to earthquake or volcanic eruption), from the official CMS tabular data.

Summary

These codes can be reported together when both conditions are documented, because X35.XXXS lists X37.41 under Excludes2, which marks them as distinct conditions.

Official rule

What is different?

The conditions named and billing status.X35.XXXS is “Volcanic eruption, sequela”; X37.41 is “Tidal wave due to earthquake or volcanic eruption”. X37.41 is a non-billable header; X35.XXXS is billable.

Registry fact

Can these codes be reported together?

Yes, when both are documented.X35.XXXS lists X37.41 under Excludes2: “tidal wave (tsunami) due to volcanic eruption (X37.41)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code.

Official rule

Is there an Excludes2 relationship?

Yes.X35.XXXS’s tabular entry: “tidal wave (tsunami) due to volcanic eruption (X37.41)”. The note covers X37.41.

Official ruleGuide: Excludes1 vs Excludes2

Is one more specific?

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

Is one a parent or header code?

One is a header.X37.41 is a non-billable header, but X35.XXXS is not one of its subdivisions.

Registry fact

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

X35.XXXS

Volcanic eruption, sequela

↔

X37.41

Tidal wave due to earthquake or volcanic eruption

What we found

Yes, when both are documented.X35.XXXS carries an Excludes2 note covering X37.41: “tidal wave (tsunami) due to volcanic eruption (X37.41)”

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 Excludes2 Check 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 FY2026

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

	X35.XXXSVolcanic eruption, sequela	X37.41Tidal wave due to earthquake or volcanic eruption
Billing status	Billable	Non-billable header Report instead: X37.41XA, X37.41XD, X37.41XS
Classification	V00-Y99 — External Causes of Morbidity (V00-Y99)	V00-Y99 — External Causes of Morbidity (V00-Y99)
Definition	Volcanic eruption, sequela is a billable ICD-10-CM diagnosis code (X35.XXXS).	Tidal wave due to earthquake or volcanic eruption is a non-billable ICD-10-CM category code (X37.41).
7th character	The appropriate 7th character is to be added to code X35	The appropriate 7th character is to be added to each code from category X37
Includes	—	Tidal wave NOS Tsunami
Excludes2	tidal wave (tsunami) due to volcanic eruption (X37.41)	—

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.

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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