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V99 vs X00-X08

V99 (Unspecified transport accident) compared with X00-X08 (Exposure to smoke, fire and flames (X00-X08)), 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 X00-X08 lists V99 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named.V99 is “Unspecified transport accident”; X00-X08 is “Exposure to smoke, fire and flames (X00-X08)”.

Registry fact

Can these codes be reported together?

Yes, when both are documented.X00-X08 lists V99 under Excludes2: “transport accident (V01-V99)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

Yes.X00-X08’s tabular entry: “transport accident (V01-V99)”. The note covers V99.

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. V99 carries 1 Excludes1 note and X00-X08 carries 1 Excludes1 note 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

X00-X08
Exposure to smoke, fire and flames (X00-X08)
↔
V99
Unspecified transport accident

What we found

Yes, when both are documented.X00-X08 carries an Excludes2 note covering V99: “transport accident (V01-V99)”

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
V99

Unspecified transport accident

X00-X08

Exposure to smoke, fire and flames (X00-X08)

StatusDiffers
V99
Non-billable header

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

Report instead: V99.XXXA, V99.XXXD, V99.XXXS

X00-X08
Non-billable header

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

Excludes1Differs
V99
  • vehicle accident, type of vehicle unspecified (V89.-)
X00-X08
  • arson (X97)
Excludes2Differs
V99

None at this code

X00-X08
  • explosions (W35-W40)
  • lightning (T75.0-)
  • transport accident (V01-V99)
CategoryDiffers
V99

Is itself a category

X00-X08

X00 Exposure to uncontrolled fire in building or structure

ChapterSame for both

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

7th characterDiffers
V99
  • The appropriate 7th character is to be added to code V99
X00-X08

None at this code

No Code first, Use additional code, Code also and Includes 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.

Edit this comparisonCheck a whole claim

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