Exposure to excessive natural cold (X31) ICD-10-CM
The X31 code range covers exposure to excessive natural cold with 4 ICD-10-CM diagnosis codes. 3 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Inclusion Terms
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
- Excessive cold as the cause of chilblains NOS
- Excessive cold as the cause of immersion foot or hand
- Exposure to cold NOS
- Exposure to weather conditions
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
- cold of man-made origin W93
- contact with or inhalation of dry ice W93
- contact with or inhalation of liquefied gas W93
7th Character Note
Certain ICD-10-CM categories have applicable 7th characters. The applicable 7th character is required for all codes within the category, or as the notes in the Tabular List instruct. The 7th character must always be the 7th character in the data field. If a code that requires a 7th character is not 6 characters, a placeholder X must be used to fill in the empty characters.
- The appropriate 7th character is to be added to code X31
7th Character
Indicates that a seventh character is to be assigned to codes in a subcategory.
- A - initial encounter
- D - subsequent encounter
- S - sequela
Codes in the X31 Range 4 codes · 3 billable
About the X31 Code Range
This group of ICD-10 codes defines health events related to exposure to excessive natural cold, such as hypothermia or injuries caused by cold weather. The primary code is X31, with extensions that specify the stage of care: initial, subsequent, or sequela.
The ICD-10 code for exposure to excessive natural cold (X31) covers medical encounters resulting from situations like a cold wave or accidents due to excessive cold. Common terms linked to these codes include hypothermia, exposure to cold environment, and injuries caused by cold weather. The seventh-character extensions—X31.XXXA for initial encounter, X31.XXXD for subsequent encounter, and X31.XXXS for sequela—help clinicians and coders identify the specific timing and nature of treatment. This coding system ensures precise documentation of cold-related injuries and conditions, aiding appropriate care and reporting for conditions caused by natural cold exposure.
Questions About This Page
How many billable codes are in the X31 range?
Of the 4 codes in this range, 3 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the X31 range classify?
The range classifies exposure to excessive natural cold. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
