ICD-10-CM 2027 diagnosis code
W57.XXXABitten or stung by nonvenomous insect and other nonvenomous arthropods, initial encounter
W57.XXXA is a valid, billable ICD-10-CM code for bitten or stung by nonvenomous insect and other nonvenomous arthropods, initial encounter. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.Short description: Bit/stung by nonvenom insect & oth nonvenom arthropods, init
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About W57.XXXA
W57.XXXA is the ICD-10-CM diagnosis code for Bitten or stung by nonvenomous insect and other nonvenomous arthropods, initial encounter. It belongs to category W57 (Bitten or stung by nonvenomous insect and other nonvenomous arthropods), block W50-W64 (exposure to animate mechanical forces) and chapter 20 (external causes of morbidity). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
The 7th character "A" means initial encounter: use it while the patient is receiving active treatment for the condition.
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Before ICD-10, this condition was coded in ICD-9-CM as E906.4 (bite of nonvenomous arthropod).
7th character
Ainitial encounter
Other encounter types for W57:
Notes that apply from higher levels
Instructions written at a parent level also apply to W57.XXXA.
Broader instructions also apply from W50-W64 Exposure to animate mechanical forces and Chapter 20: External causes of morbidity.
ICD-9-CM equivalent
Converter →- E906.4Bite of nonvenomous arthropodapproximate
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about W57.XXXA
Is W57.XXXA billable?
- Yes. W57.XXXA is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
What does the "A" at the end of W57.XXXA mean?
- It is the 7th character for initial encounter. Per the official guidelines, use it while the patient is receiving active treatment for the condition.
Can W57.XXXA be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict W57.XXXA as a principal diagnosis.
Is W57.XXXA a CC or MCC?
- No. W57.XXXA is neither a CC nor an MCC under MS-DRG v44.0.
What is the ICD-9 code for W57.XXXA?
- The CMS General Equivalence Mappings map W57.XXXA to ICD-9-CM E906.4.