ICD-10-CM 2027 diagnosis code

X31Exposure to excessive natural cold

Not billable — use a more specific code

X31 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About X31

X31 is the ICD-10-CM diagnosis code for exposure to excessive natural cold. It belongs to block X30-X39 (exposure to forces of nature) and chapter 20 (external causes of morbidity). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: X31.XXXA (initial encounter), X31.XXXD (subsequent encounter) and X31.XXXS (sequela).

Don't report X31 together with the conditions in its Excludes1 note: cold of man-made origin (W93.-), contact with or inhalation of dry ice (W93.-) and contact with or inhalation of liquefied gas (W93.-).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under X31

Coding notes

Applicable toConditions and synonyms classified to this 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

Excludes1Not coded here — never report together with this code

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

Notes that apply from higher levels

Instructions written at a parent level also apply to X31.

Broader instructions also apply from Chapter 20: External causes of morbidity.

Alphabetic index entries

6 entries

Terms in the official ICD-10-CM index that lead to X31.

Codes whose notes reference X31

T68Use additional code
T69Use additional code

Code history

2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027

FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
No changes since FY2016.

Common questions about X31

Is X31 billable?: No. X31 is a header code. Report one of its more specific subcodes instead.