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T59.821S ICD-10-CM Code: Toxic effect of hexamethylene diisocyanate, accidental (unintentional), sequela

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

Code Set: New for FY2027 — not valid before October 1, 2026.

Code Overview

No additional overview provided for this record.

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for T59.821S in the official ICD-10-CM tabular list.

Includes

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

  • aerosol propellants inherited from T59

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Toxic effects of hexamethylene diisocyanate NOS inherited from T59.821

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): inherited from T51-T65
  • for all associated manifestations of toxic effect, such as: respiratory conditions due to external agents (J60-J70) inherited from T51-T65
  • personal history of foreign body fully removed (Z87.821) inherited from T51-T65
  • to identify any retained foreign body, if applicable (Z18.-) inherited from T51-T65

Frequently Compared Codes

The official Excludes notes on T59.821S name these codes. Each comparison page covers when the two can — or must not — be reported together.

Change history

  • Upcoming · effective FY2027 — 2026-10-01
    Will be added to the code set
    Toxic effect of hexamethylene diisocyanate, accidental (unintentional), sequela
    FY2027 changes

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 T59.821S 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 (via T59.-).

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

Related Codes

Same injury, other encounter phase

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

T59.821A — Toxic effect of hexamethylene diisocyanate, accidental (unintentional), initial encounter Compare T59.821S vs T59.821A →, T59.821D — Toxic effect of hexamethylene diisocyanate, accidental (unintentional), subsequent encounter

Contextual Map

Every relationship of T59.821S 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.

Hierarchy

  • S00-T88 — Chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) (S00-T88) [Hierarchy]
  • T51-T65 — Toxic effects of substances chiefly nonmedicinal as to source [Hierarchy]

Referenced by Excludes1 notes

  • T71 — Asphyxiation [Excludes1](via T59.-): “asphyxia from other gases, fumes and vapors (T59.-)” · check together

Nearest codes (40)

  • T59 — Toxic effect of other gases, fumes and vapors [Sibling]
  • T59.811 — Toxic effect of smoke, accidental (unintentional) [Sibling]
  • T59.811A — Toxic effect of smoke, accidental (unintentional), initial encounter [Sibling]
  • T59.811D — Toxic effect of smoke, accidental (unintentional), subsequent encounter [Sibling]
  • T59.811S — Toxic effect of smoke, accidental (unintentional), sequela [Sibling]
  • T59.812 — Toxic effect of smoke, intentional self-harm [Sibling]
  • T59.812A — Toxic effect of smoke, intentional self-harm, initial encounter [Sibling]
  • T59.812D — Toxic effect of smoke, intentional self-harm, subsequent encounter [Sibling]
  • and 32 more

Change history

  • FY2027 — Will be added to the code set [Change history]

Frequently Asked Questions (FAQ) & Clinical Guidance

Does T59.821S require a 7th character?

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

Nearest Codes in This Family

Official ICD-10-CM classifications closest to T59.821S in its code family, with their registry titles.

  • T59.814S — Toxic effect of smoke, undetermined, sequela
  • T59.82 — Toxic effects of hexamethylene diisocyanate
  • T59.821 — Toxic effect of hexamethylene diisocyanate, accidental (unintentional)
  • T59.821A — Toxic effect of hexamethylene diisocyanate, accidental (unintentional), initial encounter
  • T59.821D — Toxic effect of hexamethylene diisocyanate, accidental (unintentional), subsequent encounter
  • T59.822 — Toxic effect of hexamethylene diisocyanate, intentional self-harm
  • T59.822A — Toxic effect of hexamethylene diisocyanate, intentional self-harm, initial encounter
  • T59.822D — Toxic effect of hexamethylene diisocyanate, intentional self-harm, subsequent encounter
  • T59.822S — Toxic effect of hexamethylene diisocyanate, intentional self-harm, sequela
  • T59.823 — Toxic effect of hexamethylene diisocyanate, assault

View all codes in the T59 family