2026 ICD-10-CM Diagnosis Code R94.121Abnormal vestibular function study

ICD-10-CM Codes›R00–R99›R90-R94›R94

ICD-10-CM R94.121
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

R94.121 is a billable ICD-10-CM diagnosis code for abnormal vestibular function study. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 154 through 156. As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established. Coders also document this condition as audiogram bilateral abnormality. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Abnormal findings without diagnosis.

Code Identity

ICD-10-CM Code
R94.121
Billable Status
Yes — Valid for Submission
Code Describes
Abnormal vestibular function study
Short Description
Abnormal vestibular function study
Same as the full description in the CMS dataset.
Parent Code
R94.12
Abnormal results of function studies of ear and other special senses

Code Classification

ChapterR00–R99Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
SectionR90-R94Abnormal findings on diagnostic imaging and in function studies, without diagnosis
CategoryR94Abnormal results of function studies
This CodeR94.121Abnormal vestibular function study

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Audiogram bilateral abnormality
  • Audiogram left abnormality
  • Audiogram right abnormality
  • Auditory/vestibular test abnormal
  • Hearing test abnormal
  • Hearing test bilateral abnormality
  • Hearing test left abnormality
  • Hearing test right abnormality

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Abnormal, abnormality, abnormalities
      • function studies
        • vestibular

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR SYM017
Abnormal findings without diagnosis
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Balance Problems

Have you ever felt dizzy, lightheaded, or as if the room is spinning around you? If the feeling happens often, it could be a sign of a balance problem. Balance problems can make you feel unsteady. You may also have blurred vision, confusion, and disorientation.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert R94.121 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
794.16 Abn vestibular func stud
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About R94.121Overview

Is R94.121 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report abnormal vestibular function study on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does R94.121 group to?

When abnormal vestibular function study is the principal diagnosis on an inpatient stay, it groups to MS-DRG 154, 155, 156, with relative weights from 0.6911 to 1.5635 depending on complications. Higher weights mean higher Medicare reimbursement.

Can R94.121 be a principal diagnosis?

Use it with care. This is a symptom code, so once a definitive diagnosis explaining the abnormal vestibular function study is established, that condition takes the principal position instead.

What is the ICD-9 equivalent of R94.121?

Under the General Equivalence Mappings, abnormal vestibular function study converts to ICD-9-CM 794.16 (abn vestibular func stud). The mapping is a direct match.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.