2026 ICD-10-CM Diagnosis Code R94.131Abnormal electromyogram [EMG]

ICD-10-CM Codes›R00–R99›R90-R94›R94

ICD-10-CM R94.131
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

R94.131 is a billable ICD-10-CM diagnosis code for abnormal electromyogram [EMG]. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 564 through 566. 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
R94.131
Billable Status
Yes — Valid for Submission
Code Describes
Abnormal electromyogram [EMG]
Short Description
Abnormal electromyogram [EMG]
Same as the full description in the CMS dataset.
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 CodeR94.131Abnormal electromyogram [EMG]

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Anodal opening clonus
  • Asymmetry of F-wave
  • Asymmetry of H-response
  • Cathodal closure clonus
  • Cathodal opening clonus
  • Complex repetitive EMG discharges
  • Continuous motor unit activity
  • Decreased frequency of F-wave
  • Early recruitment of short duration polyphasic motor unit with abnormal spontaneous activity on electromyogram
  • Early recruitment of short duration polyphasic motor unit without abnormal spontaneous activity on electromyogram
  • Electrical EMG silence
  • Electromyogram abnormal
  • EMG decelerating bursts
  • EMG interference pattern - finding
  • EMG positive sharp waves
  • Exaggeration of H-response
  • F-wave finding
  • High amplitude reduced interference pattern with abnormal spontaneous activity on electromyogram
  • High amplitude reduced interference pattern without abnormal spontaneous activity on electromyogram
  • Increased chronodispersion of F-wave
  • Increased insertional activity
  • Increased latency of F-wave
  • Increased latency of H-response
  • Increased tacheodispersion of F-wave
  • Indeterminate EMG pattern
  • Interference pattern showing early recruitment
  • Interference pattern showing increased amplitude
  • Interference pattern showing reduced amplitude
  • Interference pattern showing reduced density
  • Loss of H-response
  • Motor unit characteristics - finding
  • Motor unit morphology - finding
  • Motor unit stability - finding
  • Motor units with extra discharges
  • Overall EMG pattern - finding
  • Polyphasic units
  • Polyphasic units - long duration - finding
  • Polyphasic units - short duration - finding
  • Reaction of degeneration by electromyogram
  • Reaction of denervation by electromyogram
  • Single muscle fiber finding
  • Single muscle fiber jitter
  • Spontaneous EMG activity
  • Stable motor units
  • Stalberg cloud
  • Unstable motor units

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Type 1 Excludes

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
      • electromyogram [EMG]

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

Muscle Disorders

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Read the full article at MedlinePlus

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

Convert R94.131 to ICD-9-CMHistory

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

ICD-9-CM
794.17 Abnorm electromyogram
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 R94.131Overview

Is R94.131 a billable code?

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

What MS-DRG does R94.131 group to?

When abnormal electromyogram [EMG] is the principal diagnosis on an inpatient stay, it groups to MS-DRG 564, 565, 566, with relative weights from 0.7493 to 1.5436 depending on complications. Higher weights mean higher Medicare reimbursement.

Can R94.131 be a principal diagnosis?

Use it with care. This is a symptom code, so once a definitive diagnosis explaining the abnormal electromyogram [EMG] is established, that condition takes the principal position instead.

What is the ICD-9 equivalent of R94.131?

Under the General Equivalence Mappings, abnormal electromyogram [EMG] converts to ICD-9-CM 794.17 (abnorm electromyogram). 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.