2026 ICD-10-CM Diagnosis Code X31Exposure to excessive natural cold

ICD-10-CM CodesV01–Y99X30-X39X31

ICD-10-CM X31
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

X31 is a non-billable ICD-10-CM category code for exposure to excessive natural cold, so it cannot be submitted on claims. Use a more specific code from this category instead, such as X31.XXXA, X31.XXXD, and X31.XXXS.

Code Identity

ICD-10-CM Code
X31
Billable Status
No — Non-Billable Category
Code Describes
Exposure to excessive natural cold
Chapter
X30-X39
Exposure to forces of nature

Code Classification

ChapterV01–Y99External causes of morbidity and mortality
SectionX30-X39Exposure to forces of nature
CategoryX31Exposure to excessive natural cold
This CodeX31Exposure to excessive natural cold

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

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

Type 1 Excludes

  • 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

  • The appropriate 7th character is to be added to code X31

7th Character

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Patient EducationClinical

Hypothermia

Cold weather can affect your body in different ways. You can get frostbite, which is an injury to the body that is caused by freezing. Your body can also lose heat faster than you can produce it. That can cause hypothermia, or abnormally low body temperature. It can make you sleepy, confused, and clumsy.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About X31Overview

Is X31 (Exposure to excessive natural cold) a billable code?

No. This is a category header that groups the codes for exposure to excessive natural cold, and headers cannot be submitted on claims. Claims for exposure to excessive natural cold need a more specific code from this category, such as X31.XXXA, X31.XXXD, and X31.XXXS.