2024 ICD-10-CM Diagnosis Code T40.604A

Poisoning by unspecified narcotics, undetermined, initial encounter

ICD-10-CM Code:
T40.604A
ICD-10 Code for:
Poisoning by unsp narcotics, undetermined, init encntr
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Not chronic
Code Navigator:

Code Classification

  • Injury, poisoning and certain other consequences of external causes
    (S00–T88)
    • Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances
      (T36-T50)
      • Poisoning by, adverse effect of and underdosing of narcotics and psychodysleptics [hallucinogens]
        (T40)

T40.604A is a billable diagnosis code used to specify a medical diagnosis of poisoning by unspecified narcotics, undetermined, initial encounter. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024.

T40.604A is an initial encounter code, includes a 7th character and should be used while the patient is receiving active treatment for a condition like poisoning by unspecified narcotics undetermined. According to ICD-10-CM Guidelines an "initial encounter" doesn't necessarily means "initial visit". The 7th character should be used when the patient is undergoing active treatment regardless if new or different providers saw the patient over the course of a treatment. The appropriate 7th character codes should also be used even if the patient delayed seeking treatment for a condition.

Unspecified diagnosis codes like T40.604A are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Approximate Synonyms

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

  • Overdose of opiate

Clinical Classification

Clinical CategoryCCSR Category CodeInpatient Default CCSROutpatient Default CCSR
External cause codes: intent of injury, undeterminedEXT023N - Not default inpatient assignment for principal diagnosis or first-listed diagnosis.N - Not default outpatient assignment for principal diagnosis or first-listed diagnosis.
External cause codes: poisoning by drugEXT014N - Not default inpatient assignment for principal diagnosis or first-listed diagnosis.N - Not default outpatient assignment for principal diagnosis or first-listed diagnosis.
Opioid-related disordersMBD018N - Not default inpatient assignment for principal diagnosis or first-listed diagnosis.N - Not default outpatient assignment for principal diagnosis or first-listed diagnosis.
Poisoning by drugs, initial encounterINJ022Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.

Coding Guidelines

When coding a poisoning or reaction to the improper use of a medication (e.g., overdose, wrong substance given or taken in error, wrong route of administration), first assign the appropriate code from categories T36-T50. The poisoning codes have an associated intent as their 5th or 6th character (accidental, intentional self-harm, assault and undetermined. If the intent of the poisoning is unknown or unspecified, code the intent as accidental intent. The undetermined intent is only for use if the documentation in the record specifies that the intent cannot be determined. Use additional code(s) for all manifestations of poisonings.

The appropriate 7th character is to be added to each code from block Poisoning by, adverse effect of and underdosing of narcotics and psychodysleptics [hallucinogens] (T40). Use the following options for the aplicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Convert T40.604A to ICD-9-CM

  • ICD-9-CM Code: 965.09 - Poisoning-opiates NEC
    Combination Flag - Multiple codes are needed to describe the source diagnosis code. Correct coding should be done based on contextual judgment.
  • ICD-9-CM Code: E980.4 - Undet pois-med agnt NEC
    Combination Flag - Multiple codes are needed to describe the source diagnosis code. Correct coding should be done based on contextual judgment.

Table of Drugs and Chemicals

The parent code T40.604 of the current diagnosis code is referenced in the Table of Drugs and Chemicals, this table contains a classification of drugs, industrial solvents, corrosive gases, noxious plants, pesticides, and other toxic agents.

According to ICD-10-CM coding guidelines it is advised to do not code directly from the Table of Drugs and Chemicals, instead always refer back to the Tabular List when doing the initial coding. Each substance in the table is assigned a code according to the poisoning classification and external causes of adverse effects. It is important to use as many codes as necessary to specify all reported drugs, medicinal or chemical substances. If the same diagnosis code describes the causative agent for more than one adverse reaction, poisoning, toxic effect or underdosing, utilize the code only once.

Substance Poisoning
Accidental
(unintentional)
Poisoning
Accidental
(self-harm)
Poisoning
Assault
Poisoning
Undetermined
Adverse
effect
Underdosing
Narcotic (drug)T40.601T40.602T40.603T40.604T40.605T40.606
Narcotic (drug)
  »analgesic NEC
T40.601T40.602T40.603T40.604T40.605T40.606
Narcotic (drug)
  »antagonist
T40.601T40.602T40.603T40.604T40.605T40.606
Narcotic (drug)
  »specified NEC
T40.601T40.602T40.603T40.604T40.605T40.606
Narcotic (drug)
  »synthetic
T40.601T40.602T40.603T40.604T40.605T40.606
Opiate NECT40.601T40.602T40.603T40.604T40.605T40.606
Opiate NEC
  »antagonists
T40.601T40.602T40.603T40.604T40.605T40.606

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • 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. This was the first year ICD-10-CM was implemented into the HIPAA code set.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.