2026 ICD-10-CM Diagnosis Code R94.09Abnormal results of other function studies of central nervous system

ICD-10-CM Codes›R00–R99›R90-R94›R94

ICD-10-CM R94.09
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

R94.09 is a billable ICD-10-CM diagnosis code for abnormal results of other function studies of central nervous system. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Abnormal findings without diagnosis.

Code Identity

ICD-10-CM Code
R94.09
Billable Status
Yes — Valid for Submission
Code Describes
Abnormal results of other function studies of central nervous system
Short Description
Abnormal results of function studies of cnsl
Parent Code
R94.0
Abnormal results of function studies of central nervous system

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 CodeR94.09Abnormal results of other function studies of central nervous system

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormal auditory evoked potential
  • Abnormal brain stem auditory evoked potential
  • Abnormal cerebral evoked potential
  • Abnormal nervous system function
  • Abnormal results function studies of central nervous system
  • Abnormal waves II through V of brainstem AEP
  • Auditory evoked potential wave I latency normal with increased latencies - all other waves
  • Brainstem auditory evoked potential finding
  • Cerebral alteration
  • Increased amplitude of cortical somatosensory evoked potential
  • Increased latency of brainstem AEP wave I
  • Increased neural tube defects detected multiple marker screening
  • Increased time interval between wave III-wave V of brainstem auditory evoked potential
  • Increased time interval between wave I-wave III of brainstem auditory evoked potential
  • Only wave I of brainstem auditory evoked potential seen
  • Phase-related abnormality of brainstem AEP
  • Raised wave V threshold of brainstem AEP

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
        • brain
    • Abnormal, abnormality, abnormalities
      • function studies
        • nervous system
          • central NEC

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

Convert R94.09 to ICD-9-CMHistory

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

ICD-9-CM
794.00 Abn cns funct study NOS
Approximate The match is approximate rather than exact.
ICD-9-CM
794.09 Abn cns funct study NEC
Approximate The match is approximate rather than exact.

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 R94.09Overview

Is R94.09 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report abnormal results of other function studies of central nervous system on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Can R94.09 be a principal diagnosis?

Use it with care. This is a symptom code, so once a definitive diagnosis explaining the abnormal results of other function studies of central nervous system is established, that condition takes the principal position instead.

What is the ICD-9 equivalent of R94.09?

Under the General Equivalence Mappings, abnormal results of other function studies of central nervous system converts to ICD-9-CM 794.00 (abn cns funct study NOS) and 794.09 (abn cns funct study NEC). The mapping is approximate, so confirm the match fits the documentation.

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.