X31 Exposure to excessive natural cold

✓ Billable ICD-10-CM 2026
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The ICD-10-CM code for Exposure to excessive natural cold is X31 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Section
X30-X39: Exposure to forces of nature (X30-X39)
Category X31
1 code (1 billable)
FY2026 Status
Stable since FY2024
Excludes1
Not coded here. These conditions should NOT be coded 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.-)

Inclusion Terms

  • 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

Official Coding Guidelines

Other external cause issues—when not direct hurricane result

c. Other External Causes of Morbidity Code Issues For injuries that are not a direct result of the hurricane, such as an evacuee that has incurred an injury as a result of a motor vehicle accident, assign the appropriate external cause of morbidity code(s) to describe the cause of the injury, but do not assign code X37.0-, Hurricane. If it is not clear whether the injury was a direct result of the hurricane, assume the injury is due to the hurricane and assign code X37.0-, Hurricane, as well as any other applicable external cause of morbidity codes. In addition to code X37.0-, Hurricane, other possible applicable external cause of morbidity codes include: X30-, Exposure to excessive natural heat X31-, Exposure to excessive natural cold X38-, Flood

— ICD-10-CM Official Guidelines for Coding and Reporting, FY2026, Section I.B.19.c
Used with any code in range A00.0-T88.9, Z00-Z99

1) Used with any code in the range of A00.0-T88.9, Z00-Z99 An external cause code may be used with any code in the range of A00.0-T88.9, Z00-Z99, classification that represents a health condition due to an external cause. Though they are most applicable to injuries, they are also valid for use with such things as infections or diseases due to an external source, and other health conditions, such as a heart attack that occurs during strenuous physical activity.

— ICD-10-CM Official Guidelines for Coding and Reporting, FY2026, Section I.C.20.a.1

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

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Reviewed by Prajwal Shrestha, CPC, CRC
Certified Professional Coder (CPC) and Certified Risk Adjustment Coder (CRC) · AAPC Member ID 01997614 · About · Editorial policy · Content last reviewed: 2025-10-01

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