A85.0 ICD-10-CM Code: Enteroviral encephalitis
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FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Viral and prion infections of the central nervous system (A80-A89)
A85.0
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceEnteroviral encephalitis
This is a brain inflammation caused by enterovirus infection, which is a type of virus that commonly affects the digestive system but can spread to the brain. Symptoms may include fever, headache, confusion, and in severe cases, seizures or loss of consciousness.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
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Code Book Path
Inclusion Terms
Official- Enteroviral encephalomyelitis
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for A85.0 in this effective period.
Related Child Codes
Includes
Official- specified viral encephalomyelitis NEC
- specified viral meningoencephalitis NEC
Excludes 1
Official- 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)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for A85.0 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for A85.0 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for A85.0 in this effective period.
Buddy Documentation Tip
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is A85.0 an HCC code?
No. A85.0 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
A85.0 is the ICD-10-CM diagnosis code for enteroviral encephalitis. This is a brain inflammation caused by enterovirus infection, which is a type of virus that commonly affects the digestive system but can spread to the brain. Symptoms may include fever, headache, confusion, and in severe cases, seizures or loss of consciousness. A85.0 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering viral and prion infections of the central nervous system (a80-a89).
A85.0 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Verify the specific enterovirus type if documented (such as Coxsackievirus or Echovirus) as this may allow for more specific coding with a fifth character.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A85.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify the specific enterovirus type if documented (such as Coxsackievirus or Echovirus) as this may allow for more specific coding with a fifth character
- •Ensure the diagnosis specifies encephalitis (brain inflammation) rather than meningitis or other CNS involvement, as these have different codes