T65.854D ICD-10-CM Code: Toxic effect of medetomidine, undetermined, subsequent encounter
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.
Official Registry Overview & Definition
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for T65.854D in the official ICD-10-CM tabular list.
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).
- contact with and (suspected) exposure to toxic substances (Z77.-) Compare T65.854D vs Z77 →
Use Additional Code
Supplementary codes the tabular list directs you to add.
- Use additional code to identify associated manifestations, such as:
- bradycardia NOS (R00.1)
- somnolence, stupor and coma (R40.-)
- 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.-)
Associated Substances (1)
Substances from the official ICD-10-CM Table of Drugs and Chemicals that map to this code.
- Medetomidine
Frequently Compared Codes
The official Excludes notes on T65.854D name these codes. Each comparison page covers when the two can — or must not — be reported together.
Change history
- FY2027 — 2026-10-01Added to the code setToxic effect of medetomidine, undetermined, subsequent encounterFY2027 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.
Related Codes
Same injury, other encounter phase
Same injury, coded at a different phase of treatment via the 7th character.
T65.854A — Toxic effect of medetomidine, undetermined, initial encounter Compare T65.854D vs T65.854A →, T65.854S — Toxic effect of medetomidine, undetermined, sequela
Contextual Map
Every relationship of T65.854D 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]
Drugs & chemicals
- Medetomidine — Medetomidine — Poisoning, Undetermined [Drug table]: “Medetomidine (Poisoning, Undetermined)”
Nearest codes (40)
- T65 — Toxic effect of other and unspecified substances [Sibling]
- T65.843S — Toxic effect of xylazine, assault, sequela [Sibling]
- T65.844 — Toxic effect of xylazine, undetermined [Sibling]
- T65.844A — Toxic effect of xylazine, undetermined, initial encounter [Sibling]
- T65.844D — Toxic effect of xylazine, undetermined, subsequent encounter [Sibling]
- T65.844S — Toxic effect of xylazine, undetermined, sequela [Sibling]
- T65.85 — Toxic effect of medetomidine [Sibling]
- T65.851 — Toxic effect of medetomidine, accidental (unintentional) [Sibling]
- and 32 more
Change history
- FY2027 — Added to the code set [Change history]
Frequently Asked Questions (FAQ) & Clinical Guidance
Does T65.854D require a 7th character?
Yes. The appropriate 7th character is to be added to each code from category T65.
Nearest Codes in This Family
Official ICD-10-CM classifications closest to T65.854D in its code family, with their registry titles.
- T65.853A — Toxic effect of medetomidine, assault, initial encounter
- T65.853D — Toxic effect of medetomidine, assault, subsequent encounter
- T65.853S — Toxic effect of medetomidine, assault, sequela
- T65.854 — Toxic effect of medetomidine, undetermined
- T65.854A — Toxic effect of medetomidine, undetermined, initial encounter
- T65.854S — Toxic effect of medetomidine, undetermined, sequela
- T65.89 — Toxic effect of other specified substances
- T65.891 — Toxic effect of other specified substances, accidental (unintentional)
- T65.891A — Toxic effect of other specified substances, accidental (unintentional), initial encounter
- T65.891D — Toxic effect of other specified substances, accidental (unintentional), subsequent encounter