2027 ICD-10-CM Diagnosis Code A89Unspecified viral infection of central nervous system
ICD-10-CM Codes›A00–B99›A80-A89›A89
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Not Chronic
A89 is a billable ICD-10-CM diagnosis code for unspecified viral infection of central nervous system. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 97 through 99, 974 through 976. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 186 closely related codes. Coders also document this condition as viral infection of central nervous system. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified CNS infection and poliomyelitis and Viral infection.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Viral infection of central nervous system
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to A89: its own notes plus those printed at block A80-A89 and Chapter 1. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- diseases generally recognized as communicable or transmissible
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may 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)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify resistance to antimicrobial drugs (Z16.-)
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Neurologic Diseases
The brain, spinal cord, and nerves make up the nervous system. Together they control all the workings of the body. When something goes wrong with a part of your nervous system, you can have trouble moving, speaking, swallowing, breathing, or learning. You can also have problems with your memory, senses, or mood.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert A89 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About A89Overview
What is the ICD-10 code for unspecified viral infection of central nervous system?
The ICD-10-CM code for unspecified viral infection of central nervous system is A89. It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is A89 (Unspecified viral infection of central nervous system) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report unspecified viral infection of central nervous system on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does A89 group to?
When unspecified viral infection of central nervous system is the principal diagnosis on an inpatient stay, it groups to MS-DRG 98, 974, 976, 99, 975, 97, with relative weights from 0.7879 to 3.8208 depending on complications. Higher weights mean higher Medicare reimbursement.
Is A89 a CC or MCC?
CMS lists A89 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 186 closely related codes in its exclusion list.
Can A89 be reported with G14?
Not as a rule. The Excludes1 note at block A80-A89, which applies to A89, lists "postpolio syndrome (G14)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
