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ICD-10-CM 2027 diagnosis code

T50.A9Poisoning by, adverse effect of and underdosing of other bacterial vaccines

Not billable — use a more specific codeRequires 7th character

T50.A9 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: Bacterial vaccines

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About T50.A9

T50.A9 is the ICD-10-CM diagnosis code for poisoning by, adverse effect of and underdosing of other bacterial vaccines. 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.A, choose T50.A9 (other bacterial vaccines) only when documentation doesn't support a more specific option: pertussis vaccine, including combinations with a pertussis component (T50.A1) and mixed bacterial vaccines without a pertussis component (T50.A2).

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 has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

7th character

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

  • Ainitial encounter
  • Dsubsequent encounter
  • Ssequela

Notes that apply from higher levels

Instructions written at a parent level also apply to T50.A9.

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
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about T50.A9

Is T50.A9 billable?

No. T50.A9 is a header code. Report one of its more specific subcodes instead.