2021 ICD-10-CM Code T40.991S

Poisoning by other psychodysleptics [hallucinogens], accidental (unintentional), sequela

Version 2021
Replaced Code
Billable Code
7th Character Code
Sequela Code
MS-DRG Mapping
POA Exempt

Valid for Submission

T40.991S is a billable diagnosis code used to specify a medical diagnosis of poisoning by other psychodysleptics [hallucinogens], accidental (unintentional), sequela. The code T40.991S is valid during the fiscal year 2021 from October 01, 2020 through September 30, 2021 for the submission of HIPAA-covered transactions.

The ICD-10-CM code T40.991S might also be used to specify conditions or terms like accidental mescaline overdose, accidental poisoning by hallucinogens, accidental poisoning by hallucinogens, accidental poisoning by hallucinogens, accidental poisoning by mescaline , accidental poisoning by psilocin, etc. The code is exempt from present on admission (POA) reporting for inpatient admissions to general acute care hospitals.

T40.991S is a sequela code, includes a 7th character and should be used for complications that arise as a direct result of a condition like poisoning by other psychodysleptics [hallucinogens] accidental (unintentional). According to ICD-10-CM Guidelines a "sequela" code should be used for chronic or residual conditions that are complications of an initial acute disease, illness or injury. The most common sequela is pain. Usually, two diagnosis codes are needed when reporting sequela. The first code describes the nature of the sequela while the second code describes the sequela or late effect.

ICD-10:T40.991S
Short Description:Poisoning by oth psychodyslept, accidental, sequela
Long Description:Poisoning by other psychodysleptics [hallucinogens], accidental (unintentional), sequela

Code Classification

Replaced Code

This code was replaced in the 2021 ICD-10 code set with the code(s) listed below. The National Center for Health Statistics (NCHS) has published an update to the ICD-10-CM diagnosis codes which became effective October 1, 2020. This code was replaced for the FY 2021 (October 1, 2020 - September 30, 2021).


  • K59.03 - Drug induced constipation

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

Present on Admission (POA)

T40.991S is exempt from POA reporting - The Present on Admission (POA) indicator is used for diagnosis codes included in claims involving inpatient admissions to general acute care hospitals. POA indicators must be reported to CMS on each claim to facilitate the grouping of diagnoses codes into the proper Diagnostic Related Groups (DRG). CMS publishes a listing of specific diagnosis codes that are exempt from the POA reporting requirement. Review other POA exempt codes here .

CMS POA Indicator Options and Definitions
POA Indicator CodePOA Reason for CodeCMS will pay the CC/MCC DRG?
YDiagnosis was present at time of inpatient admission.YES
NDiagnosis was not present at time of inpatient admission.NO
UDocumentation insufficient to determine if the condition was present at the time of inpatient admission.NO
WClinically undetermined - unable to clinically determine whether the condition was present at the time of inpatient admission.YES
1Unreported/Not used - Exempt from POA reporting. NO

Convert T40.991S to ICD-9 Code

Code History

  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016 (First year ICD-10-CM implemented into the HIPAA code set)