Exposure to high and low air pressure and changes in air pressure (W94) ICD-10-CM
The W94 code range covers exposure to high and low air pressure and changes in air pressure with 44 ICD-10-CM diagnosis codes. 30 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
7th Character Note
Certain ICD-10-CM categories have applicable 7th characters. The applicable 7th character is required for all codes within the category, or as the notes in the Tabular List instruct. The 7th character must always be the 7th character in the data field. If a code that requires a 7th character is not 6 characters, a placeholder X must be used to fill in the empty characters.
- The appropriate 7th character is to be added to each code from category W94
7th Character
Indicates that a seventh character is to be assigned to codes in a subcategory.
- A - initial encounter
- D - subsequent encounter
- S - sequela
Codes in the W94 Range 44 codes · 30 billable
- W94 Exposure to high and low air pressure and changes in air pressureNon-billable
- W94.0 Exposure to prolonged high air pressureNon-billable
- W94.0XXA Exposure to prolonged high air pressure, initial encounter
- W94.0XXD Exposure to prolonged high air pressure, subsequent encounter
- W94.0XXS Exposure to prolonged high air pressure, sequela
- W94.1 Exposure to prolonged low air pressureNon-billable
- W94.11 Exposure to residence or prolonged visit at high altitudeNon-billable
- W94.11XA Exposure to residence or prolonged visit at high altitude, initial encounter
- W94.11XD Exposure to residence or prolonged visit at high altitude, subsequent encounter
- W94.11XS Exposure to residence or prolonged visit at high altitude, sequela
- W94.12 Exposure to other prolonged low air pressureNon-billable
- W94.12XA Exposure to other prolonged low air pressure, initial encounter
- W94.12XD Exposure to other prolonged low air pressure, subsequent encounter
- W94.12XS Exposure to other prolonged low air pressure, sequela
- W94.2 Exposure to rapid changes in air pressure during ascentNon-billable
- W94.21 Exposure to reduction in atmospheric pressure while surfacing from deep-water divingNon-billable
- W94.21XA Exposure to reduction in atmospheric pressure while surfacing from deep-water diving, initial encounter
- W94.21XD Exposure to reduction in atmospheric pressure while surfacing from deep-water diving, subsequent encounter
- W94.21XS Exposure to reduction in atmospheric pressure while surfacing from deep-water diving, sequela
- W94.22 Exposure to reduction in atmospheric pressure while surfacing from undergroundNon-billable
- W94.22XA Exposure to reduction in atmospheric pressure while surfacing from underground, initial encounter
- W94.22XD Exposure to reduction in atmospheric pressure while surfacing from underground, subsequent encounter
- W94.22XS Exposure to reduction in atmospheric pressure while surfacing from underground, sequela
- W94.23 Exposure to sudden change in air pressure in aircraft during ascentNon-billable
- W94.23XA Exposure to sudden change in air pressure in aircraft during ascent, initial encounter
- W94.23XD Exposure to sudden change in air pressure in aircraft during ascent, subsequent encounter
- W94.23XS Exposure to sudden change in air pressure in aircraft during ascent, sequela
- W94.29 Exposure to other rapid changes in air pressure during ascentNon-billable
- W94.29XA Exposure to other rapid changes in air pressure during ascent, initial encounter
- W94.29XD Exposure to other rapid changes in air pressure during ascent, subsequent encounter
- W94.29XS Exposure to other rapid changes in air pressure during ascent, sequela
- W94.3 Exposure to rapid changes in air pressure during descentNon-billable
- W94.31 Exposure to sudden change in air pressure in aircraft during descentNon-billable
- W94.31XA Exposure to sudden change in air pressure in aircraft during descent, initial encounter
- W94.31XD Exposure to sudden change in air pressure in aircraft during descent, subsequent encounter
- W94.31XS Exposure to sudden change in air pressure in aircraft during descent, sequela
- W94.32 Exposure to high air pressure from rapid descent in waterNon-billable
- W94.32XA Exposure to high air pressure from rapid descent in water, initial encounter
- W94.32XD Exposure to high air pressure from rapid descent in water, subsequent encounter
- W94.32XS Exposure to high air pressure from rapid descent in water, sequela
- W94.39 Exposure to other rapid changes in air pressure during descentNon-billable
- W94.39XA Exposure to other rapid changes in air pressure during descent, initial encounter
- W94.39XD Exposure to other rapid changes in air pressure during descent, subsequent encounter
- W94.39XS Exposure to other rapid changes in air pressure during descent, sequela
About the W94 Code Range
These codes describe exposure to prolonged high or low air pressure and rapid pressure changes during ascent or descent.
The main subdivisions separate prolonged high pressure (W94.0) from prolonged low pressure (W94.1). They also separate rapid changes during ascent (W94.2) from those during descent (W94.3). Low-pressure codes distinguish high-altitude residence or prolonged visits from other prolonged exposure. Ascent codes distinguish surfacing from deep-water diving or underground, aircraft pressure changes, and other rapid changes. Descent codes distinguish aircraft pressure changes, rapid descent in water, and other rapid changes. The final character marks an initial encounter (A), subsequent encounter (D), or later effect (S).
Questions About This Page
How many billable codes are in the W94 range?
Of the 44 codes in this range, 30 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the W94 range classify?
The range classifies exposure to high and low air pressure and changes in air pressure. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
