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ICD-10-CM 2027 diagnosis code

A85Other viral encephalitis, not elsewhere classified

Not billable — use a more specific code

A85 is a header code, so it can't be reported by itself. Choose one of the 4 more specific codes beneath it.

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 A85

A85 is the ICD-10-CM diagnosis code for other viral encephalitis, not elsewhere classified. It belongs to block A80-A89 (viral and prion infections of the central nervous system) and chapter 1 (certain infectious and parasitic diseases). It is a header code, so it can't be reported by itself; one of its 4 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: A85.0 (encephalitis), A85.1 (encephalitis), A85.2 (unspecified) and A85.8 (encephalitis).

Don't report A85 together with the conditions in its Excludes1 note: encephalitis due to cytomegalovirus (B25.8), encephalitis due to herpesvirus NEC (B10.0-), encephalitis due to herpesvirus [herpes simplex] (B00.4), encephalitis due to measles virus (B05.0) and 5 more.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under A85

Coding notes

IncludesFurther defines the content of the category
  • specified viral encephalomyelitis NEC
  • specified viral meningoencephalitis NEC
Excludes1Not coded here — never report together with this code
  • encephalitis due to cytomegalovirus (B25.8)
  • encephalitis due to herpesvirus NEC (B10.0-)
  • encephalitis due to herpesvirus [herpes simplex] (B00.4)
  • encephalitis due to measles virus (B05.0)
  • encephalitis due to mumps virus (B26.2)
  • encephalitis due to poliomyelitis virus (A80.-)
  • encephalitis due to zoster (B02.0)
  • lymphocytic choriomeningitis (A87.2)
  • myalgic encephalomyelitis (G93.32)

Notes that apply from higher levels

Instructions written at a parent level also apply to A85.

Broader instructions also apply from A80-A89 Viral and prion infections of the central nervous system and Chapter 1: Certain infectious and parasitic diseases.

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 A85

Is A85 billable?

No. A85 is a header code. Report one of its more specific subcodes instead.