2026 ICD-10-CM Diagnosis Code T67.3XXAHeat exhaustion, anhydrotic, initial encounter
T67.3XXA is a billable ICD-10-CM diagnosis code for heat exhaustion, anhydrotic, 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 anhidrosis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Effect of other external causes, initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Anhidrosis
- Heat exhaustion
- Heat exhaustion co-occurrent and due to anhidrosis
- Heat-induced dermatosis
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.
Clinical InformationClinical
Heat Exhaustion
a clinical syndrome caused by heat stress, such as over-exertion in a hot environment or excessive exposure to sun. it is characterized by sweating, water (volume) depletion, salt depletion, cool clammy skin, nausea, and headache.
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.
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Convert T67.3XXA to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T67.3XXAOverview
Is T67.3XXA (Heat exhaustion, anhydrotic) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report heat exhaustion, anhydrotic, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T67.3XXA mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for heat exhaustion, anhydrotic, such as an emergency visit or first evaluation.
What MS-DRG does T67.3XXA group to?
When heat exhaustion, anhydrotic, 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 T67.3XXA?
Under the General Equivalence Mappings, heat exhaustion, anhydrotic, initial encounter converts to ICD-9-CM 992.3 (heat exhaust-anhydrotic). 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.
