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ICD-10-CM 2027 diagnosis code

T50.91Poisoning by, adverse effect of and underdosing of multiple unspecified drugs, medicaments and biological substances

Not billable — use a more specific codeRequires 7th character

T50.91 is a header code, so it can't be reported by itself. Choose one of the 6 more specific codes beneath it and add the required 7th character.Short description: Multiple unspecified drug/meds/biol subst

Code last changed in FY2020 (effective October 1, 2019). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About T50.91

T50.91 is the ICD-10-CM diagnosis code for poisoning by, adverse effect of and underdosing of multiple unspecified drugs, medicaments and biological substances. It belongs to category T50 (poisoning by, adverse effect of and underdosing of diuretics and other and unspecified drugs, medicaments and biological substances), block T36-T50 (poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances) 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 6 subcodes must be used instead.

Within T50.9, choose T50.91 (multiple unspecified drugs, medicaments and biological substances) only when documentation doesn't support a more specific option: unspecified drugs, medicaments and biological substances (T50.90) and other drugs, medicaments and biological substances (T50.99).

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 FY2020, effective October 1, 2019.

7th character

The appropriate 7th character is to be added to each code from category T50

  • Ainitial encounter
  • Dsubsequent encounter
  • Ssequela

Coding notes

Applicable toConditions and synonyms classified to this code
  • Multiple drug ingestion NOS
Code alsoTwo codes may be needed; sequencing depends on circumstances
  • any specific drugs, medicaments and biological substances

Notes that apply from higher levels

Instructions written at a parent level also apply to T50.91.

Broader instructions also apply from T36-T50 Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances and Chapter 19: Injury, poisoning and certain other consequences of external causes.

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
  • FY2020 (effective 10/1/2019): Added
  • No changes since FY2020.

Common questions about T50.91

Is T50.91 billable?

No. T50.91 is a header code. Report one of its more specific subcodes instead.