2026 ICD-10-CM Diagnosis Code T34.522AFrostbite with tissue necrosis of left hand, initial encounter
T34.522A is a billable ICD-10-CM diagnosis code for frostbite with tissue necrosis of left hand, 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. 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.
- Frostbite of left hand
- Frostbite of left thumb
- Frostbite of left upper limb
- Frostbite of thumb
- Tissue necrosis of hand due to and following frostbite
- Tissue necrosis of left hand due to and following frostbite
- Tissue necrosis of left thumb due to and following frostbite
- Tissue necrosis of left upper limb due to and following frostbite
- Tissue necrosis of thumb due to and following frostbite
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Frostbite with tissue necrosis (T34). 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.
Patient EducationClinical
Frostbite
Frostbite is an injury to the body that is caused by freezing. It most often affects the nose, ears, cheeks, chin, fingers, or toes. Frostbite can permanently damage the body, and severe cases can lead to amputation.
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Convert T34.522A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T34.522AOverview
Is T34.522A (Frostbite with tissue necrosis of left hand) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report frostbite with tissue necrosis of left hand, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T34.522A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for frostbite with tissue necrosis of left hand, such as an emergency visit or first evaluation.
What MS-DRG does T34.522A group to?
When frostbite with tissue necrosis of left hand, 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 T34.522A?
Under the General Equivalence Mappings, frostbite with tissue necrosis of left hand, initial encounter converts to ICD-9-CM 991.1 (frostbite of hand). 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.
