FY2027 ICD-10-CM reference
A83: Mosquito-borne viral encephalitis
By the HCC Buddy Coding Team
The official ICD-10-CM descriptor is Mosquito-borne viral encephalitis. 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.
CMS-HCC V28
Not applicable to this nonbillable heading
CMS-HCC V24
Not applicable to this nonbillable heading
ESRD
Not applicable to this nonbillable heading
PACE
Not applicable to this nonbillable heading
RxHCC
Not applicable to this nonbillable heading
HHS-HCC
Not applicable to this nonbillable heading
More specific FY2027 codes
- A83.0: Japanese encephalitisBillable code
- A83.1: Western equine encephalitisBillable code
- A83.2: Eastern equine encephalitisBillable code
- A83.3: St Louis encephalitisBillable code
- A83.4: Australian encephalitisBillable code
- A83.5: California encephalitisBillable code
- A83.6: Rocio virus diseaseBillable code
- A83.8: Other mosquito-borne viral encephalitisBillable code
- A83.9: Mosquito-borne viral encephalitis, 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
mosquito-borne viral meningoencephalitis
Source: A83 (category, direct).
Excludes2
Venezuelan equine encephalitis (A92.2)
Source: A83 (category, direct).
Excludes2
West Nile fever (A92.3-)
Source: A83 (category, direct).
Excludes2
West Nile virus (A92.3-)
Source: A83 (category, direct).
Compare the FY2027 additions, removals and billable-status changes
What does A83 mean in FY2027?
The official ICD-10-CM descriptor is Mosquito-borne viral encephalitis. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Is A83 billable in FY2027?
The FY2027 order file marks A83 as a nonbillable heading. Select a complete billable child code.
Does A83 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