ICD-10-CM 2027 diagnosis code
T45.3Poisoning by, adverse effect of and underdosing of enzymes
T45.3 is a header code, so it can't be reported by itself. Choose one of the 1 more specific codes beneath it and add the required 7th character.
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 T45.3
T45.3 is the ICD-10-CM diagnosis code for poisoning by, adverse effect of and underdosing of enzymes. It belongs to category T45 (poisoning by, adverse effect of and underdosing of primarily systemic and hematological agents, not elsewhere classified), 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 1 subcodes must be used instead.
Within T45 (poisoning by, adverse effect of and underdosing of primarily systemic and hematological agents, not elsewhere classified), T45.3 is specifically for poisoning by, adverse effect of and underdosing of enzymes. Related codes cover antiallergic and antiemetic drugs (T45.0), antineoplastic and immunosuppressive drugs (T45.1), vitamins (T45.2), iron and its compounds (T45.4), anticoagulants and antithrombotic drugs (T45.5), fibrinolysis-affecting drugs (T45.6), anticoagulant antagonists, vitamin K and other coagulants (T45.7), other primarily systemic and hematological agents (T45.8) and 2 more.
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 T45
- Ainitial encounter
- Dsubsequent encounter
- Ssequela
Notes that apply from higher levels
Instructions written at a parent level also apply to T45.3.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about T45.3
Is T45.3 billable?
- No. T45.3 is a header code. Report one of its more specific subcodes instead.