2026 ICD-10-CM Diagnosis Code T41.46XAUnderdosing of unspecified anesthetics, initial encounter

ICD-10-CM Codes›S00–T88›T36-T50›T41

ICD-10-CM T41.46XA
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

T41.46XA is a billable ICD-10-CM diagnosis code for underdosing of unspecified anesthetics, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is not accepted as a principal diagnosis by the Medicare Code Editor. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Underdosing of drugs and medicaments, initial encounter.

Code Identity

ICD-10-CM Code
T41.46XA
Billable Status
Yes — Valid for Submission
Code Describes
Underdosing of unspecified anesthetics, initial encounter
Short Description
Underdosing of unspecified anesthetics, initial encounter
Same as the full description in the CMS dataset.
Parent Code
T41.46
Underdosing of unspecified anesthetics

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT36-T50Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances
CategoryT41Poisoning by, adverse effect of and underdosing of anesthetics and therapeutic gases
This CodeT41.46XAUnderdosing of unspecified anesthetics, initial encounter

Code EditsBilling

Medicare Code Editor checks that affect claim validity for T41.46XA.

Unacceptable principal diagnosis
There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Coding GuidelinesGuidance

Underdosing refers to taking less of a medication than is prescribed by a provider or a manufacturer's instruction. Codes for underdosing should never be assigned as principal or first-listed codes. If a patient has a relapse or exacerbation of the medical condition for which the drug is prescribed because of the reduction in dose, then the medical condition itself should be coded.

The appropriate 7th character is to be added to each code from block Poisoning by, adverse effect of and underdosing of anesthetics and therapeutic gases (T41). Use the following options for the applicable episode of care:

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

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ029
Underdosing of drugs and medicaments, initial encounter
Default principal diagnosis: inpatient No · outpatient No

Table of Drugs and ChemicalsClinical

Substances in the Table of Drugs and Chemicals that reference this code family. Always confirm in the Tabular List before coding.

SubstanceAccidentalSelf-harmAssaultUndeter­minedAdverse
Effect		Under­dosing
Anesthetic NEC [See Also: Anesthesia]T41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::with muscle relaxantT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::with muscle relaxant::generalT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::with muscle relaxant::localT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::gaseous NECT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::general NECT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::halogenated hydrocarbon derivatives NECT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::infiltration NECT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::intravenous NECT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::local NECT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::rectalT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::rectal::generalT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::rectal::localT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::regional NECT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::spinal NECT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::thiobarbiturateT41.41T41.42T41.43T41.44T41.45T41.46
Anesthetic NEC [See Also: Anesthesia]::topicalT41.41T41.42T41.43T41.44T41.45T41.46

Patient EducationClinical

Anesthesia

Anesthesia is the use of medicines, called anesthetics, to prevent pain during surgery and other medical procedures. Medicine may be given by injection, inhalation, topical lotion, spray, eye drops, or a skin patch.

The full article covers:

  • What is anesthesia?
  • What is anesthesia used for?
  • What are the types of anesthesia?
  • What are the risks of anesthesia?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert T41.46XA to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
No Map There is no ICD-9 equivalent for this code.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About T41.46XAOverview

Is T41.46XA (Underdosing of unspecified anesthetics) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report underdosing of unspecified anesthetics, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in T41.46XA mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for underdosing of unspecified anesthetics, such as an emergency visit or first evaluation.

Can T41.46XA be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because underdosing of unspecified anesthetics, initial encounter describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

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.