2026 ICD-10-CM Diagnosis Code T41.0X6AUnderdosing of inhaled anesthetics, initial encounter
T41.0X6A is a billable ICD-10-CM diagnosis code for underdosing of inhaled 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
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for T41.0X6A.
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.
Clinical InformationClinical
Enflurane
an extremely stable inhalation anesthetic that allows rapid adjustments of anesthesia depth with little change in pulse or respiratory rate.Halothane
a nonflammable, halogenated, hydrocarbon anesthetic that provides relatively rapid induction with little or no excitement. analgesia may not be adequate. nitrous oxide is often given concomitantly. because halothane may not produce sufficient muscle relaxation, supplemental neuromuscular blocking agents may be required. (from ama drug evaluations annual, 1994, p178)Isoflurane
a stable, non-explosive inhalation anesthetic, relatively free from significant side effects.Methoxyflurane
an inhalation anesthetic. currently, methoxyflurane is rarely used for surgical, obstetric, or dental anesthesia. if so employed, it should be administered with nitrous oxide to achieve a relatively light level of anesthesia, and a neuromuscular blocking agent given concurrently to obtain the desired degree of muscular relaxation. (from ama drug evaluations annual, 1994, p180)
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.
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 T41.0X6A to ICD-9-CMHistory
Code HistoryHistory
Questions About T41.0X6AOverview
Is T41.0X6A (Underdosing of inhaled anesthetics) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report underdosing of inhaled anesthetics, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T41.0X6A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for underdosing of inhaled anesthetics, such as an emergency visit or first evaluation.
Can T41.0X6A be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because underdosing of inhaled 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.
