ICD-10-CM 2027 diagnosis code
Y21.4XXSDrowning and submersion in natural water, undetermined intent, sequela
Y21.4XXS is a valid, billable ICD-10-CM code for drowning and submersion in natural water, undetermined intent, sequela. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.Short description: Drown in natural water, undetermined intent, sequela
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 Y21.4XXS
Y21.4XXS is the ICD-10-CM diagnosis code for drowning and submersion in natural water, undetermined intent, sequela. It belongs to category Y21 (drowning and submersion, undetermined intent), block Y21-Y33 (event of undetermined intent) 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 "S" means sequela: use it for complications or conditions that arise as a direct result of the original condition.
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
It is exempt from present-on-admission (POA) reporting, so no POA indicator is required.
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 E929.8 (late effects of other accidents).
7th character
Ssequela
Other encounter types for Y21.4:
Notes that apply from higher levels
Instructions written at a parent level also apply to Y21.4XXS.
Broader instructions also apply from Y21-Y33 Event of undetermined intent and Chapter 20: External causes of morbidity.
ICD-9-CM equivalent
Converter →- E929.8Late effects of other accidentsapproximate
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 Y21.4XXS
Is Y21.4XXS billable?
- Yes. Y21.4XXS is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
What does the "S" at the end of Y21.4XXS mean?
- It is the 7th character for sequela. Per the official guidelines, use it for complications or conditions that arise as a direct result of the original condition.
Can Y21.4XXS be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Y21.4XXS as a principal diagnosis.
Is Y21.4XXS a CC or MCC?
- No. Y21.4XXS is neither a CC nor an MCC under MS-DRG v44.0.
What is the ICD-9 code for Y21.4XXS?
- The CMS General Equivalence Mappings map Y21.4XXS to ICD-9-CM E929.8.