2027 ICD-10-CM Diagnosis Code X31Exposure to excessive natural cold

ICD-10-CM Codes›V01–Y99›X30-X39›X31

ICD-10-CM X31
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

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
Short Description
Exposure to excessive natural cold
Same as the full description in the CMS dataset.
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

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to X31: its own notes plus those printed at Chapter 20. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • 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

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

  • cold of man-made origin (W93.-)
  • contact with or inhalation of dry ice (W93.-)
  • contact with or inhalation of liquefied gas (W93.-)

Notes

General instructions on how these codes are used.

From Chapter 20 (V00-Y99) External causes of morbidity and mortality applies to 7,461 codes
  • This chapter permits the classification of environmental events and circumstances as the cause of injury, and other adverse effects. Where a code from this section is applicable, it is intended that it shall be used secondary to a code from another chapter of the Classification indicating the nature of the condition. Most often, the condition will be classifiable to Chapter 19, Injury, poisoning and certain other consequences of external causes (S00-T88). Other conditions that may be stated to be due to external causes are classified in Chapters I to XVIII. For these conditions, codes from Chapter 20 should be used to provide additional information as to the cause of the condition.

7th Character

Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.

  • The appropriate 7th character is to be added to code X31
Values for category X31 Encounter: Initial, Subsequent, Sequela
  • Ainitial encounter
  • Dsubsequent encounter
  • Ssequela

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name X31, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming X31: they are not reported together with it, unless the two conditions are unrelated.

  • Block W85-W99 Exposure to electric current, radiation and extreme ambient air temperature and pressure
    natural cold (X31)

Use Additional Code 2

These codes say to use an additional code from the note, and X31 is one of the codes named.

  • T68 Hypothermia
    Exposure to excessive cold of natural origin (X31)
  • T69 Other effects of reduced temperature
    Exposure to excessive cold of natural origin (X31)

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index; each main term links to its index entry.

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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About X31Overview

What is the ICD-10 code for exposure to excessive natural cold?

X31 is the ICD-10-CM category for exposure to excessive natural cold, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

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.

Can X31 be reported with a code from W93?

Not as a rule. The Excludes1 note on X31 lists "cold of man-made origin (W93.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).