Exposure to ionizing radiation (W88) ICD-10-CM
The W88 code range covers exposure to ionizing radiation with 13 ICD-10-CM diagnosis codes. 9 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
- exposure to sunlight X32
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 W88
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 W88 Range 13 codes · 9 billable
- W88 Exposure to ionizing radiationNon-billable
- W88.0 Exposure to X-raysNon-billable
- W88.0XXA Exposure to X-rays, initial encounter
- W88.0XXD Exposure to X-rays, subsequent encounter
- W88.0XXS Exposure to X-rays, sequela
- W88.1 Exposure to radioactive isotopesNon-billable
- W88.1XXA Exposure to radioactive isotopes, initial encounter
- W88.1XXD Exposure to radioactive isotopes, subsequent encounter
- W88.1XXS Exposure to radioactive isotopes, sequela
- W88.8 Exposure to other ionizing radiationNon-billable
- W88.8XXA Exposure to other ionizing radiation, initial encounter
- W88.8XXD Exposure to other ionizing radiation, subsequent encounter
- W88.8XXS Exposure to other ionizing radiation, sequela
About the W88 Code Range
Exposure to X-rays, radioactive isotopes, or other ionizing radiation appears here as an external cause.
W88 separates exposure to X-rays, radioactive isotopes, and other ionizing radiation. For each type, the final character distinguishes an initial encounter (A), a subsequent encounter (D), or a sequela (S), meaning a later effect.
Questions About This Page
How many billable codes are in the W88 range?
Of the 13 codes in this range, 9 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 W88 range classify?
The range classifies exposure to ionizing radiation. 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.
