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ICD-10-CM 2027 diagnosis code

Y33.XXXAOther specified events, undetermined intent, initial encounter

✓ Billable / specificRequires 7th character

Y33.XXXA is a valid, billable ICD-10-CM code for other specified events, undetermined intent, initial encounter. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.Short description: Other specified events, undetermined intent, init encntr

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 Y33.XXXA

Y33.XXXA is the ICD-10-CM diagnosis code for other specified events, undetermined intent, initial encounter. It belongs to category Y33 (other specified events, 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 "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 E988.8 (injury by other specified means, undetermined whether accidentally or purposely inflicted).

7th character

Ainitial encounter

Other encounter types for Y33:

Notes that apply from higher levels

Instructions written at a parent level also apply to Y33.XXXA.

Broader instructions also apply from Y21-Y33 Event of undetermined intent and Chapter 20: External causes of morbidity.

ICD-9-CM equivalent

Converter →
  • E988.8Injury by other specified means, undetermined whether accidentally or purposely inflictedapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about Y33.XXXA

Is Y33.XXXA billable?

Yes. Y33.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 Y33.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 Y33.XXXA be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict Y33.XXXA as a principal diagnosis.

Is Y33.XXXA a CC or MCC?

No. Y33.XXXA is neither a CC nor an MCC under MS-DRG v44.0.

What is the ICD-9 code for Y33.XXXA?

The CMS General Equivalence Mappings map Y33.XXXA to ICD-9-CM E988.8.