2026 ICD-10-CM Diagnosis Code R94.138Abnormal results of other function studies of peripheral nervous system

ICD-10-CM Codes›R00–R99›R90-R94›R94

ICD-10-CM R94.138
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

R94.138 is a billable ICD-10-CM diagnosis code for abnormal results of other function studies of peripheral 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
R94.138
Billable Status
Yes — Valid for Submission
Code Describes
Abnormal results of other function studies of peripheral nervous system
Short Description
Abnormal results of function studies of prph nervous sys
Parent Code
R94.13
Abnormal results of function studies of peripheral 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 CodeR94.138Abnormal results of other function studies of peripheral nervous system

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormal axonal conduction
  • Abnormal evoked potential
  • Abnormal nerve conduction
  • Abnormal results function studies peripheral nervous system special senses
  • Abnormal saltatory conduction
  • Diffuse mixed nerve conduction abnormality
  • Diffuse motor nerve conduction abnormality
  • Diffuse sensory nerve conduction abnormality
  • Focal mixed nerve conduction slowing
  • Focal motor nerve conduction slowing
  • Focal sensory nerve conduction slowing
  • Increased polarization of nerve cell and nerve fiber
  • Left motor nerve conduction block
  • Left sensory nerve conduction block
  • Mixed nerve conduction block
  • Mixed nerve conduction pattern - finding
  • Motor nerve conduction block
  • Motor nerve conduction block - excessive
  • Motor nerve conduction block - full
  • Motor nerve conduction block - partial
  • Motor nerve conduction block - patchy
  • Right motor nerve conduction block
  • Right sensory nerve conduction block
  • Sensory nerve conduction block
  • Sensory nerve conduction block - excessive
  • Sensory nerve conduction block - full
  • Sensory nerve conduction block - inadequate caudad spread
  • Sensory nerve conduction block - inadequate cephalad spread
  • Sensory nerve conduction block - partial
  • Sensory nerve conduction block - patchy

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
      • caloric test
    • Abnormal, abnormality, abnormalities
      • function studies
        • nervous system
          • peripheral 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

Patient EducationClinical

Peripheral Nerve Disorders

Nerves are like wires that carry messages back and forth between your brain and your body. Your peripheral nerves branch off from your brain and spinal cord and connect to all parts of your body, including your muscles and organs.

The full article covers:

  • What are peripheral nerves?
  • What are peripheral nerve disorders?
  • What causes peripheral nerve disorders?
  • What are the symptoms of peripheral nerve disorders?
  • How are peripheral nerve disorders diagnosed?
  • What are the treatments for peripheral nerve disorders?
  • Can peripheral nerve disorders be prevented?

Read the full article at MedlinePlus

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

Convert R94.138 to ICD-9-CMHistory

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

ICD-9-CM
794.19 Abn periph nerv stud 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 R94.138Overview

Is R94.138 a billable code?

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

Can R94.138 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 peripheral nervous system is established, that condition takes the principal position instead.

What is the ICD-9 equivalent of R94.138?

Under the General Equivalence Mappings, abnormal results of other function studies of peripheral nervous system converts to ICD-9-CM 794.19 (abn periph nerv stud 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.