2026 ICD-10-CM Diagnosis Code T67.6XXAHeat fatigue, transient, initial encounter

ICD-10-CM Codes›S00–T88›T66-T78›T67

ICD-10-CM T67.6XXA
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

T67.6XXA is a billable ICD-10-CM diagnosis code for heat fatigue, transient, 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) and groups to MS-DRG 922 through 923. Coders also document this condition as transient heat fatigue. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Effect of other external causes, initial encounter.

Code Identity

ICD-10-CM Code
T67.6XXA
Billable Status
Yes — Valid for Submission
Code Describes
Heat fatigue, transient, initial encounter
Short Description
Heat fatigue, transient, initial encounter
Same as the full description in the CMS dataset.
Parent Code
T67.6
Heat fatigue, transient

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT66-T78Other and unspecified effects of external causes
CategoryT67Effects of heat and light
This CodeT67.6XXAHeat fatigue, transient, initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Transient heat fatigue

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Effects of heat and light (T67). 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 INJ021
Effect of other external causes, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Heat Illness

Your body normally cools itself by sweating. During hot weather, especially when it is very humid, sweating just isn't enough to cool you off. Your body temperature can rise to dangerous levels and you can develop a heat illness.

Read the full article at MedlinePlus

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

Convert T67.6XXA to ICD-9-CMHistory

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

ICD-9-CM
992.6 Heat fatigue, transient
Approximate The match is approximate rather than exact.

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 T67.6XXAOverview

Is T67.6XXA (Heat fatigue, transient) a billable code?

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

What does the 7th character A in T67.6XXA mean?

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

What MS-DRG does T67.6XXA group to?

When heat fatigue, transient, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 922, 923, with relative weights from 1.0177 to 1.7494 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of T67.6XXA?

Under the General Equivalence Mappings, heat fatigue, transient, initial encounter converts to ICD-9-CM 992.6 (heat fatigue, transient). The mapping is approximate, so confirm the match fits the documentation.

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.