ICD-10 X31
Non-Billable HeaderExposure to excessive natural cold
About ICD-10-CM X31
ICD-10-CM code X31 represents Exposure to excessive natural cold. This is a non-billable header code in the External Causes of Morbidity chapter (block X31). The 2026 edition of ICD-10-CM X31 became effective on October 1, 2025. Non-billable codes cannot be used as a primary or secondary diagnosis on a claim, use a more specific child code instead.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under X31. Per CMS ICD-10-CM Tabular 2026.
- 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
Pure excludes, these codes can never be coded together with X31. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- cold of man-made origin (W93.-)
- contact with or inhalation of dry ice (W93.-)
- contact with or inhalation of liquefied gas (W93.-)
Coding Notes
Seven Chr Note
- The appropriate 7th character is to be added to code X31
Medicare LCD Coverage for X31
Local Coverage Determinations (LCDs) from CMS MACs that list X31 as a covered diagnosis.
This doesn't mean the code isn't covered, it means no MAC has issued a Local Coverage Determination naming this specific code. Coverage may still apply under National Coverage Determinations or general medical-necessity rules.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing X31.
Our payer policy database covers Aetna, Cigna, Anthem, BCBS, Humana, and Medicare Advantage plans, but X31 doesn't currently appear in any indexed policy. The code may still be covered under standard plan benefits.
CPT Codes Commonly Billed with X31
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Codes Adjacent To X31
Other codes in section X30-X39 (Exposure to forces of nature).
ICD-10 X31, Billing FAQ
Is ICD-10 code X31 billable? +
No, X31 is a non-billable header code. Use a more specific child code from block X31 when submitting claims.
What other names or terms map to X31? +
ICD-10 X31 includes: Excessive cold as the cause of chilblains NOS; Excessive cold as the cause of immersion foot or hand; Exposure to cold NOS, and 1 more clinical synonyms.
What codes are Type 1 Excludes for X31? +
Type 1 Excludes (never code together with X31): cold of man-made origin (W93.-); contact with or inhalation of dry ice (W93.-); contact with or inhalation of liquefied gas (W93.-)
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on June 1, 2026.
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