A85.1 — Adenoviral encephalitis
A85.1 is a billable, specific ICD-10-CM code for adenoviral encephalitis. It is valid for submission on a claim.
Inclusion terms
Alternative wordings a physician may use in the chart for this same code.
- Adenoviral meningoencephalitis
Other codes that can never be billed with A85.1
These codes carry an Excludes1 note pointing at A85.1. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading A85.1 alone.
- G05Encephalitis, myelitis and encephalomyelitis in diseases classified elsewhere
Risk adjustment
A85.1 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.
Medicare coverage
A85.1 is named in 8 Medicare coverage policies — 8 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A56612Billing and Coding: CT of the Head
- A56771Billing and Coding: Special Electroencephalography
- A57204Billing and Coding: MRI and CT Scans of the Head and Neck
- A57206Billing and Coding: Lumbar MRI
How A85.1 is indexed
Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to A85.1.
- Encephalitis›in›adenovirus
Related codes at this level
Codes that share A85. If A85.1 is not quite right, the correct code is usually one of these.
Questions about A85.1
- Is A85.1 a billable ICD-10-CM code?
- Yes. A85.1 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does A85.1 sit in the tabular list?
- Certain infectious and parasitic diseases (A00-B99), in the block Viral and prion infections of the central nervous system (A80-A89).