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ICD-10-CM 2027 diagnosis code

T40.4X6AUnderdosing of other synthetic narcotics, initial encounter

Deleted in FY2021Requires 7th character

T40.4X6A was removed from ICD-10-CM in FY2021 and can't be reported for dates of service on or after October 1, 2020.

Code last changed in FY2016 (effective October 1, 2015). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About T40.4X6A

T40.4X6A was the ICD-10-CM code for underdosing of other synthetic narcotics, initial encounter until it was deleted in FY2021. It can't be reported for dates of service on or after October 1, 2020.

7th character

Ainitial encounter

Other encounter types for T40.4X6:

    Notes that apply from higher levels

    Instructions written at a parent level also apply to T40.4X6A.

    › From T40 Poisoning by, adverse effect of and underdosing of narcotics and psychodysleptics [hallucinogens]
    Excludes2
    • drug dependence and related mental and behavioral disorders due to psychoactive substance use (F10.-F19.-)

    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)
    • FY2021 (effective 10/1/2020): Deleted

    Common questions about T40.4X6A

    Is T40.4X6A billable?

    No. T40.4X6A was deleted in FY2021.