X31 — Exposure to excessive natural cold
X31 is a non-billable header ICD-10-CM code for exposure to excessive natural cold. It cannot be billed on its own: choose one of the more specific child codes below. This code also requires a 7th character before it is complete.
This code requires a 7th character
The appropriate 7th character is to be added to code X31
- A
- initial encounter
- D
- subsequent encounter
- S
- sequela
Excludes1 — never code together
These conditions cannot occur together. Billing both on the same encounter is a denial.
Inclusion terms
Alternative wordings a physician may use in the chart for this same 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
Risk adjustment
X31 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.
How X31 is indexed
Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to X31.
- Frostbite
- Exposure›cold(accidental) (excessive) (extreme) (natural) (place)
- Forces of nature›cold(natural)
- Immersion›hand or foot due to cold(excessive)
- Overexposure›cold
- Exposure›cold›due to›weather(conditions)
Code to one of these instead X31
3 child codes. Green means billable.
Questions about X31
- Is X31 a billable ICD-10-CM code?
- No. X31 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
- Where does X31 sit in the tabular list?
- External causes of morbidity (V00-Y99), in the block Exposure to forces of nature (X30-X39).
- What cannot be coded together with X31?
- X31 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.