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ICD-10-CM 2027 diagnosis code

T65.851Toxic effect of medetomidine, accidental (unintentional)

Not billable — use a more specific codeNew for 2027Requires 7th character

T65.851 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it and add the required 7th character.

Code last changed in FY2027 (effective October 1, 2026). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About T65.851

T65.851 is the ICD-10-CM diagnosis code for toxic effect of medetomidine, accidental (unintentional). It belongs to category T65 (toxic effect of other and unspecified substances), block T51-T65 (toxic effects of substances chiefly nonmedicinal as to source) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within T65.85 (toxic effect of medetomidine), T65.851 is specifically for toxic effect of medetomidine, accidental (unintentional). Related codes cover intentional self-harm (T65.852), assault (T65.853) and undetermined (T65.854).

Codes in this range require a 7th character: A for initial encounter, D for subsequent encounter and S for sequela. Use placeholder "X" characters to fill any empty positions before the 7th character.

It was added in FY2027, effective October 1, 2026.

7th character

The appropriate 7th character is to be added to each code from category T65

Coding notes

Applicable toConditions and synonyms classified to this code
  • Toxic effect of medetomidine NOS

Notes that apply from higher levels

Instructions written at a parent level also apply to T65.851.

› From T65.85 Toxic effect of medetomidine
Use additional code
  • code to identify associated manifestations, such as:
  • bradycardia NOS (R00.1)
  • somnolence, stupor and coma (R40.-)

Broader instructions also apply from T51-T65 Toxic effects of substances chiefly nonmedicinal as to source and Chapter 19: Injury, poisoning and certain other consequences of external causes.

Table of Drugs & Neoplasms entries

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2027 (effective 10/1/2026): Added

Common questions about T65.851

Is T65.851 billable?

No. T65.851 is a header code. Report one of its more specific subcodes instead.

Did T65.851 change for 2027?

Yes. For FY2027 (effective October 1, 2026) it was added to the code set.