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T56.94XS vs T57.0

T56.94XS (Toxic effect of unspecified metal, undetermined, sequela) compared with T57.0 (Toxic effect of arsenic and its compounds), from the official CMS tabular data.

Summary

These codes should not be reported together because T56.94XS’s tabular entry lists T57.0 under Excludes1.

Official rule
What is different?

Title wording and billing status.The titles share “Toxic effect of”; T56.94XS says “unspecified metal, undetermined, sequela” where T57.0 says “arsenic and its compounds”. T57.0 is a non-billable header; T56.94XS is billable.

Registry fact

Can these codes be reported together?

No.T56.94XS’s entry carries an Excludes1 note covering T57.0: “arsenic and its compounds (T57.0)”. Both may be reported only when the documentation shows the two conditions are unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

Yes.T56.94XS’s tabular entry: “arsenic and its compounds (T57.0)”. The note covers T57.0.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

None.Neither entry carries an Excludes2 note that names the other code.

Official rule

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.T57.0 is a non-billable header, but T56.94XS 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?

Conflict

Excludes1 conflict

T56.94XS
Toxic effect of unspecified metal, undetermined, sequela
↔
T57.0
Toxic effect of arsenic and its compounds

What we found

No — do not report together.T56.94XS carries an Excludes1 note covering T57.0: “arsenic and its compounds (T57.0)”

Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

What to review

Report one of the two. Both may be reported only when the documentation shows the two conditions are unrelated to each other.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes1 note means the two conditions cannot occur together, so the pair should not be reported for the same encounter. The sole exception is when the conditions are documented as unrelated to each other.

Source / rule

CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a

Official guidance behind these answers

  • Section I.A.12.a — Excludes1 · applies to: Excludes1

    A type 1 Excludes note is a pure excludes note. It means “NOT CODED HERE!” An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition. An exception to the Excludes1 definition is the circumstance when the two conditions are unrelated to each other. If it is not clear whether the two conditions involving an Excludes1 note are related or not, query the provider. For example, code F45.8, Other somatoform disorders, has an Excludes1 note for "sleep related teeth grinding (G47.63)," because "teeth grinding" is an inclusion term under F45.8. Only one of these two codes should be assigned for teeth grinding. However psychogenic dysmenorrhea is also an inclusion term under F45.8, and a patient could have both this condition and sleep related teeth grinding. In this case, the two conditions are clearly unrelated to each other, and so it would be appropriate to report F45.8 and G47.63 together.

    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

T56.94XSToxic effect of unspecified metal, undetermined, sequelaT57.0Toxic effect of arsenic and its compounds
Billing statusBillableNon-billable header

Report instead: T57.0X1A, T57.0X1D, T57.0X1S, T57.0X2A, T57.0X2D

ClassificationS00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)
DefinitionToxic effect of unspecified metal, undetermined, sequela is a billable ICD-10-CM diagnosis code (T56.94XS).Toxic effect of arsenic and its compounds is a non-billable ICD-10-CM category code (T57.0).
7th characterThe appropriate 7th character is to be added to each code from category T56The appropriate 7th character is to be added to each code from category T57
Includes
toxic effects of fumes and vapors of metals
toxic effects of metals from all sources, except medicinal substances
—
Excludes1
arsenic and its compounds (T57.0)
manganese and its compounds (T57.2)
contact with and (suspected) exposure to toxic substances (Z77.-)
contact with and (suspected) exposure to toxic substances (Z77.-)
Use additional code
code to identify any retained metal foreign body, if applicable (Z18.0-, T18.1-)
code(s):
for all associated manifestations of toxic effect, such as: respiratory conditions due to external agents (J60-J70)
code(s):
for all associated manifestations of toxic effect, such as: respiratory conditions due to external agents (J60-J70)
personal history of foreign body fully removed (Z87.821)

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 (FY2026). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources