Is ICD-10-CM code X31 billable?

No, X31 (Exposure to excessive natural cold) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code X31 belong to?

X31 belongs to Chapter 20 of the ICD-10-CM tabular list: V00–Y99 (External Causes of Morbidity).

X31Not billable, use a more specific code below

Exposure to excessive natural cold

In Exposure to forces of nature (X30-X39), chapter 20: External Causes of Morbidity

3 billable codes under X31: none are a CC or MCC; none map to an HCC.

Instructional notes

Includes: conditions that are coded here

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, use a different code

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

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Covers how to report external cause codes (V00-Y99) describing cause, intent, place, activity, and status. They are never principal or first-listed, and reporting is voluntary unless required.

General External Cause Coding Guidelines (page 88)
Place of Occurrence Guideline (page 89)
Activity Code (page 89)
Place of Occurrence, Activity, and Status Codes Used with other External Cause Code (page 89)
If the Reporting Format Limits the Number of External Cause Codes (page 90)
Multiple External Cause Coding Guidelines (page 90)
Child and Adult Abuse Guideline (page 90)
Unknown or Undetermined Intent Guideline (page 91)

Read Section I.C.20 (page 87), 3 more topics

All codes under X31

X31 can't be used on a claim. Pick a billable code below; grey headings group them.

X31 MS-DRGs

This code does not group to an MS-DRG as a principal diagnosis.

Other codes that refer to X31

Notes on these codes point to X31.

T68 Use Additional Code: Exposure to excessive cold of natural origin (X31)
T69 Use Additional Code: Exposure to excessive cold of natural origin (X31)
W85-W99 Excludes1: natural cold (X31)

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.