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T59.91XD ICD-10-CM Code: Toxic effect of unspecified gases, fumes and vapors, accidental (unintentional), subsequent encounter

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

7th character
Required — see the character table on this page
Tabular directives
1 inclusion term · 2 Excludes1 · 4 use-additional codes

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for T59.91XD in the official ICD-10-CM tabular list, quoted as published.

Notes without a marker are published on T59.91XD itself; “inherited from” names the category or block whose note applies here.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • aerosol propellants

Source: inherited from T59

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional 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.-)

Source: inherited from T51-T65

7th Character Guide

"The appropriate 7th character is to be added to each code from category T59"

  • A — initial encounter
  • D — subsequent encounter (this page’s code)
  • S — sequela

How the encounter character is assigned. “Initial encounter” means the patient is receiving active treatment for the condition — it is not limited to the first visit, and a different or new provider giving active treatment still assigns it. “Subsequent encounter” covers care during the healing or recovery phase after active treatment. “Sequela” is for complications or conditions that arise as a direct result of the original condition.

ICD-10-CM Official Guidelines for Coding and Reporting, Section I.C.19.a (paraphrased by MedCoder).

Variant codes in this family

T59.91XA, T59.91XD, T59.91XS

Character meanings are CMS's official 7th-character extensions for this family, as carried in each variant code's official description; variant codes are registry rows. The explanation of how the encounter character is assigned is MedCoder editorial, distinct from the official content above it.

Code Overview

Toxic effect of unspecified gases, fumes and vapors, accidental (unintentional), subsequent encounter is a billable ICD-10-CM diagnosis code (T59.91XD).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

  1. A 7th character applies in this family. Confirm the documented encounter matches the character assigned. See the official 7th-character definitions and this code’s variants
  2. 4 Use Additional Code instructions — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
  3. 2 Excludes1 entries — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

Other codes that name T59.91XD or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes1 note: T71 — Asphyxiation (via T59.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 11 Excludes2 notes across 2 chapters: T80 — Complications following infusion, transfusion and therapeutic injection (via T59.-), T80-T88 — Complications of surgical and medical care, not elsewhere classified (T80-T88) (via T59.-), T81 — Complications of procedures, not elsewhere classified (via T59.-), T82 — Complications of cardiac and vascular prosthetic devices, implants and grafts (via T59.-), T83 — Complications of genitourinary prosthetic devices, implants and grafts (via T59.-), T84 — Complications of internal orthopedic prosthetic devices, implants and grafts (via T59.-), T85 — Complications of other internal prosthetic devices, implants and grafts (via T59.-), T86 — Complications of transplanted organs and tissue (via T59.-), T87 — Complications peculiar to reattachment and amputation (via T59.-), T88 — Other complications of surgical and medical care, not elsewhere classified (via T59.-), Z77 — Other contact with and (suspected) exposures hazardous to health (via T59.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Referenced by 68 Code First instructions across 14 chapters: D61.2 — Aplastic anemia due to other external agents (via T59.-), D64.2 — Secondary sideroblastic anemia due to drugs and toxins (via T59.-), E03.2 — Hypothyroidism due to medicaments and other exogenous substances (via T59.-), E09 — Drug or chemical induced diabetes mellitus (via T59.-), F02 — Dementia in other diseases classified elsewhere (via T59.-), G21.2 — Secondary parkinsonism due to other external agents (via T59.-), G62.2 — Polyneuropathy due to other toxic agents (via T59.-), G70.1 — Toxic myoneural disorders (via T59.-), G72.2 — Myopathy due to other toxic agents (via T59.-), G92.8 — Other toxic encephalopathy (via T59.-), G92.9 — Unspecified toxic encephalopathy (via T59.-), H10.21 — Acute toxic conjunctivitis (via T59.-), H35.38 — Toxic maculopathy (via T59.-), H46.3 — Toxic optic neuropathy (via T59.-), H91.0 — Ototoxic hearing loss (via T59.-), I42.7 — Cardiomyopathy due to drug and external agent (via T59.-), J68 — Respiratory conditions due to inhalation of chemicals, gases, fumes and vapors (via T59.-), J69.1 — Pneumonitis due to inhalation of oils and essences (via T59.-), J69.8 — Pneumonitis due to inhalation of other solids and liquids (via T59.-), J70.8 — Respiratory conditions due to other specified external agents (via T59.-), +48 more.

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

MS-DRG Grouper Relationships (FY2026)

Not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity.

Potential MS-DRG participation — not a DRG assignment.

Named in the grouper logic of 2 MS-DRGs: DRG 949 (MDC 23), DRG 950 (MDC 23).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):INJ060 — Toxic effects, subsequent encounter (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same injury, other encounter phase

Same injury, coded at a different phase of treatment via the 7th character.

T59.91XA — Toxic effect of unspecified gases, fumes and vapors, accidental (unintentional), initial encounterCompare T59.91XD vs T59.91XA →, T59.91XS — Toxic effect of unspecified gases, fumes and vapors, accidental (unintentional), sequela

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Toxic effects, subsequent encounter).

+543 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main terms “Effect, adverse”, “Inhalation”; these codes share that main term but sit in a different category of the Tabular List.

O74.9 — Complication of anesthesia during labor and delivery, unspecified (anesthesia, in labor and delivery), O89.01 — Aspiration pneumonitis due to anesthesia during the puerperium (stomach contents or secretions, due to anesthesiaor other sedation, postpartum, puerperal), O89.3 — Toxic reaction to local anesthesia during the puerperium (anesthesia, local, toxic, postpartum, puerperal), O89.4 — Spinal and epidural anesthesia-induced headache during the puerperium (anesthesia, spinal and epidural, headache, postpartum, puerperal), O89.5 — Other complications of spinal and epidural anesthesia during the puerperium (anesthesia, spinal and epidural, specified NEC, postpartum, puerperal), O89.8 — Other complications of anesthesia during the puerperium (anesthesia, specified NEC, postpartum, puerperal), O89.9 — Complication of anesthesia during the puerperium, unspecified (anesthesia, postpartum, puerperal), P24.00 — Meconium aspiration without respiratory symptoms (meconium), P24.01 — Meconium aspiration with respiratory symptoms (meconium, with, pneumonia), T27.3 — Burn of respiratory tract, part unspecified (flame), T66 — Radiation sickness, unspecified (infrared NOS), T69.1 — Chilblains (cold, chilblains), T69.8 — Other specified effects of reduced temperature (cold, specified effect NEC), T69.9 — Effect of reduced temperature, unspecified (cold), T70.0 — Otitic barotrauma (high altitude NEC, on, ears), T70.1 — Sinus barotrauma (high altitude NEC, on, sinuses), T70.29 — Other effects of high altitude (high altitude NEC), T70.3 — Caisson disease [decompression sickness] (atmospheric pressure, high), T70.4 — Effects of high-pressure fluids (high pressure fluids), T70.8 — Other effects of air pressure and water pressure (air pressure, specified NEC), +35 more

Contextual Map

Every relationship of T59.91XD in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run T59.91XD with these 17 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

  • T71 — Asphyxiation[Excludes1](via T59.-): “asphyxia from other gases, fumes and vapors (T59.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes2 notes (11)

Referenced by Code First instructions (68)

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 23 — Factors Influencing Health Status and Other Contacts with Health Services[MDC crossing]: “Factors Influencing Health Status and Other Contacts with Health Services — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 1,235 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Nearest codes (40)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

Does T59.91XD require a 7th character?

Yes. The appropriate 7th character is to be added to each code from category T59.

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Toxic effect of unspecified gases, fumes and vapors, accidental (unintentional), subsequent encounter

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to T59.91XD in its code family, with their registry titles.

View all codes in the T59 family