Bitten or stung by nonvenomous insect and other nonvenomous arthropods (W57) ICD-10-CM
The W57 code range covers bitten or stung by nonvenomous insect and other nonvenomous arthropods with 4 ICD-10-CM diagnosis codes. 3 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.
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 code W57
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 W57 Range 4 codes · 3 billable
- W57 Bitten or stung by nonvenomous insect and other nonvenomous arthropodsNon-billable
- W57.XXXA Bitten or stung by nonvenomous insect and other nonvenomous arthropods, initial encounter
- W57.XXXD Bitten or stung by nonvenomous insect and other nonvenomous arthropods, subsequent encounter
- W57.XXXS Bitten or stung by nonvenomous insect and other nonvenomous arthropods, sequela
About the W57 Code Range
This category describes bites or stings from nonvenomous insects and other nonvenomous arthropods, including tick bites and ant stings.
The seventh character separates an initial encounter (W57.XXXA), a subsequent encounter (W57.XXXD), and a sequela, or later effect (W57.XXXS).
Questions About This Page
How many billable codes are in the W57 range?
Of the 4 codes in this range, 3 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 W57 range classify?
The range classifies bitten or stung by nonvenomous insect and other nonvenomous arthropods. 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.
