W94.1
Exposure to prolonged low air pressure
W94.1 is a non-billable ICD-10-CM code header for exposure to prolonged low air pressure. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are W94.11 Exposure to residence or prolonged visit at high altitude and W94.12 Exposure to other prolonged low air pressure. Its coding notes include 8 Excludes1 entries.
7th characters
Every code below needs one of these (defined at W94).
The appropriate 7th character is to be added to each code from category W94
- Ainitial encounter
- Dsubsequent encounter
- Ssequela
Guidelines tip
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
An external cause code is never a principal or first-listed diagnosis. Its 7th character is assigned for each encounter and should match the injury or condition code.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Also from chapter/block level (8 notes)
Notes
Also from chapter/block level (1 note)
- This chapter permits the classification of environmental events and circumstances as the cause of injury, and other adverse effects. Where a code from this section is applicable, it is intended that it shall be used secondary to a code from another chapter of the Classification indicating the nature of the condition. Most often, the condition will be classifiable to Chapter 19, Injury, poisoning and certain other consequences of external causes (S00-T88). Other conditions that may be stated to be due to external causes are classified in Chapters I to XVIII. For these conditions, codes from Chapter 20 should be used to provide additional information as to the cause of the condition.