FY2027 ICD-10-CM reference
A81: Atypical virus infections of central nervous system
By the HCC Buddy Coding Team
The official ICD-10-CM descriptor is Atypical virus infections of central nervous system. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Nonbillable heading. Verified against the official FY2027 order file.
More specific FY2027 codes
- A81.0: Creutzfeldt-Jakob diseaseNonbillable heading
- A81.1: Subacute sclerosing panencephalitisBillable code
- A81.2: Progressive multifocal leukoencephalopathyBillable code
- A81.8: Other atypical virus infections of central nervous systemNonbillable heading
- A81.9: Atypical virus infection of central nervous system, unspecifiedBillable code
FY2027 Tabular instructions
Instructions below include applicable chapter, section and parent-code notes. Each note identifies where it appears in the official source.
Includes
diseases generally recognized as communicable or transmissible
Source: A00-B99 (chapter, inherited).
Instructional note
code to identify resistance to antimicrobial drugs (Z16.-)
Source: A00-B99 (chapter, inherited).
Excludes2
carrier or suspected carrier of infectious disease (Z22.-)
Source: A00-B99 (chapter, inherited).
Excludes2
certain localized infections - see body system-related chapters
Source: A00-B99 (chapter, inherited).
Excludes2
infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
Source: A00-B99 (chapter, inherited).
Excludes2
infectious and parasitic diseases specific to the perinatal period (P35-P39)
Source: A00-B99 (chapter, inherited).
Excludes2
influenza and other acute respiratory infections (J00-J22)
Source: A00-B99 (chapter, inherited).
Excludes1
postpolio syndrome (G14)
Source: A80-A89 (section, inherited).
Excludes1
sequelae of poliomyelitis (B91)
Source: A80-A89 (section, inherited).
Excludes1
sequelae of viral encephalitis (B94.1)
Source: A80-A89 (section, inherited).
Includes
diseases of the central nervous system caused by prions
Source: A81 (category, direct).
Instructional note
code, if applicable, to identify:
Source: A81 (category, direct).
Instructional note
dementia with anxiety (F02.84, F02.A4, F02.B4, F02.C4)
Source: A81 (category, direct).
Instructional note
dementia with behavioral disturbance (F02.81-, F02.A1-, F02.B1-, F02.C1-)
Source: A81 (category, direct).
Instructional note
dementia with mood disturbance (F02.83, F02.A3, F02.B3, F02.C3)
Source: A81 (category, direct).
Instructional note
dementia with psychotic disturbance (F02.82, F02.A2, F02.B2, F02.C2)
Source: A81 (category, direct).
Instructional note
dementia without behavioral disturbance (F02.80, F02.A0, F02.B0, F02.C0)
Source: A81 (category, direct).
Instructional note
mild neurocognitive disorder due to known physiological condition (F06.7-)
Source: A81 (category, direct).
Compare the FY2027 additions, removals and billable-status changes
What does A81 mean in FY2027?
The official ICD-10-CM descriptor is Atypical virus infections of central nervous system. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Is A81 billable in FY2027?
The FY2027 order file marks A81 as a nonbillable heading. Select a complete billable child code.
Does A81 map to an HCC?
Risk-model mapping is not applicable to this nonbillable heading. Check a complete billable child code.
Source: CMS FY2027 ICD-10-CM order file. Payment model: CMS CY 2027 Rate Announcement. Read the FY2027 Official Guidelines.
Review the FY2026 April edition