A89 — Unspecified viral infection of central nervous system
Is A89 billable?
Yes, but A89 is an unspecified code. A89 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, A89 is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting A89.
A89 at a glance
| Code | A89 |
|---|---|
| Description | Unspecified viral infection of central nervous system |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does A89 group to?
A89 sits in MDC 01 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 097Non-Bacterial Infection of Nervous System Except Viral Meningitis with MCCmedical
- 098Non-Bacterial Infection of Nervous System Except Viral Meningitis with CCmedical
- 099Non-Bacterial Infection of Nervous System Except Viral Meningitis without CC/MCCmedical
As a secondary diagnosis, A89 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is A89 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to A89. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Infection, infected, infective › virus, viral NOS › central nervous system (opportunistic)
Excludes1 — never code together — inherited from A80-A89
The conditions below can never be reported together with A89 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Use additional code — inherited from Chapter 1
Report an additional code alongside A89 to fully describe the condition. A89 is sequenced first.
- code to identify resistance to antimicrobial drugs (Z16.-)
Excludes2 — not included here — inherited from Chapter 1
The conditions below are not part of A89, but a patient may have both at the same time. When documentation supports it, A89 and the excluded code may both be reported.
- carrier or suspected carrier of infectious disease (Z22.-)
- certain localized infections - see body system-related chapters
- infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
- infectious and parasitic diseases specific to the perinatal period (P35-P39)
- influenza and other acute respiratory infections (J00-J22)
How long has A89 existed?
A89 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.