W94 vs X31
W94 (Exposure to high and low air pressure and changes in air pressure) compared with X31 (Exposure to excessive natural cold), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. W94 carries an Excludes1 note covering X31: “natural cold (X31)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| W94Exposure to high and low air pressure and changes in air pressure | X31Exposure to excessive natural cold | |
|---|---|---|
| Billing status | Non-billable header Report instead: W94.0XXA, W94.0XXD, W94.0XXS, W94.11XA, W94.11XD | Non-billable header |
| Classification | V00-Y99 — External Causes of Morbidity (V00-Y99) | V00-Y99 — External Causes of Morbidity (V00-Y99) |
| Definition | Exposure to high and low air pressure and changes in air pressure is a non-billable ICD-10-CM category code (W94). | Exposure to excessive natural cold is a non-billable ICD-10-CM category code (X31). |
| 7th character | The appropriate 7th character is to be added to each code from category W94 | The appropriate 7th character is to be added to code X31 |
| Includes | — | 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 |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources