2027 ICD-10-CM Diagnosis Code T57.94XAToxic effect of unspecified inorganic substance, undetermined, initial encounter

ICD-10-CM Codes›S00–T88›T51-T65›T57

ICD-10-CM T57.94XA
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

T57.94XA is a billable ICD-10-CM diagnosis code for toxic effect of unspecified inorganic substance, undetermined, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 917 through 918. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under External cause codes: intent of injury, undetermined; External cause codes: poisoning by non-drug; and Toxic effects, initial encounter.

Code Identity

ICD-10-CM Code
T57.94XA
Billable Status
Yes — Valid for Submission
Code Describes
Toxic effect of unspecified inorganic substance, undetermined, initial encounter
Short Description
Toxic effect of unsp inorganic substance, undetermined, init
Parent Code
T57.94
Toxic effect of unspecified inorganic substance, undetermined

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT51-T65Toxic effects of substances chiefly nonmedicinal as to source
CategoryT57Toxic effect of other inorganic substances
This CodeT57.94XAToxic effect of unspecified inorganic substance, undetermined, initial encounter

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Toxic effect of other inorganic substances (T57). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027, published by CMS and the National Center for Health Statistics.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to T57.94XA: its own notes plus those printed at T57, block T51-T65, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Block T51-T65 Toxic effects of substances chiefly nonmedicinal as to source applies to 1,680 codes
  • contact with and (suspected) exposure to toxic substances (Z77.-)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Block T51-T65 Toxic effects of substances chiefly nonmedicinal as to source applies to 1,680 codes
  • 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)
  • to identify any retained foreign body, if applicable (Z18.-)
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • code to identify any retained foreign body, if applicable (Z18.-)

Notes

General instructions on how these codes are used.

From Block T51-T65 Toxic effects of substances chiefly nonmedicinal as to source applies to 1,680 codes
  • When no intent is indicated code to accidental. Undetermined intent is only for use when there is specific documentation in the record that the intent of the toxic effect cannot be determined.
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
  • The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

7th Character

Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.

From T57 Toxic effect of other inorganic substances applies to 72 codes
  • The appropriate 7th character is to be added to each code from category T57
Values for category T57 Encounter: Initial, Subsequent, Sequela
  • Ainitial encounter this code
  • Dsubsequent encounter
  • Ssequela

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR EXT023
External cause codes: intent of injury, undetermined
Default principal diagnosis: inpatient No · outpatient No
CCSR EXT015
External cause codes: poisoning by non-drug
Default principal diagnosis: inpatient No · outpatient No
CCSR INJ023
Toxic effects, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Table of Drugs and ChemicalsClinical

Substances in the Table of Drugs and Chemicals that reference this code family. Always confirm in the Tabular List before coding.

SubstanceAccidentalSelf-harmAssaultUndeter­minedAdverse
Effect		Under­dosing
Inorganic substance NECT57.91T57.92T57.93T57.94––

Convert T57.94XA to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
989.9 Tox eff nonmed subst NOS
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
E980.9 Undeter pois-sol/liq NEC
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About T57.94XAOverview

Is T57.94XA a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report toxic effect of unspecified inorganic substance, undetermined, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character A in T57.94XA mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for toxic effect of unspecified inorganic substance, undetermined, such as an emergency visit or first evaluation.

What MS-DRG does T57.94XA group to?

When toxic effect of unspecified inorganic substance, undetermined, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 918, 917, with relative weights from 0.8716 to 1.5698 depending on complications. Higher weights mean higher Medicare reimbursement.

Can T57.94XA be reported with a code from Z77?

Not as a rule. The Excludes1 note at block T51-T65, which applies to T57.94XA, lists "contact with and (suspected) exposure to toxic substances (Z77.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What is the ICD-9 equivalent of T57.94XA?

Under the General Equivalence Mappings, toxic effect of unspecified inorganic substance, undetermined, initial encounter converts to ICD-9-CM 989.9 (tox eff nonmed subst NOS) and E980.9 (undeter pois-sol/liq NEC). The mapping is approximate, so confirm the match fits the documentation.