CPT 95937 Neuromuscular Junction RNS Reimbursement | OpenPayer

Summary & Overview

CPT 95937: Neuromuscular Junction Testing by Repetitive Stimulation

CPT code 95937 denotes neuromuscular junction testing performed by repetitive nerve stimulation to evaluate disorders of neuromuscular transmission. This diagnostic electrodiagnostic procedure aids in confirming or excluding conditions that impair synaptic function at the neuromuscular junction, making it an important tool for neurologists and electrophysiology services nationwide. The code is relevant to inpatient and outpatient neurology practice, hospital-based electrophysiology labs, and specialty clinics.

Key payers covered in this overview include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the clinical purpose and typical settings for the service, an outline of common billing modifiers, and a summary of related service lines and coding relationships. The publication provides national benchmarks where available, notes on coding and coverage considerations, and clinical context to clarify appropriate application of the code. Data not available in the input for certain fields is indicated explicitly where applicable.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare95937CPTelectrodiagnosticneuromuscular junctionrepetitive nerve stimulationneurologydiagnostic testingelectrophysiology

Billing Code Overview

CPT code 95937 describes neuromuscular junction testing performed by repetitive nerve stimulation of a nerve supplying a muscle. The service is used to diagnose patients with known or suspected disorders of the neuromuscular junction, such as conditions that affect neuromuscular transmission.

Service type: Diagnostic electrodiagnostic procedure assessing neuromuscular junction function
Typical site of service: Electrophysiology laboratory, neurology clinic, or hospital outpatient setting

Clinical & Coding Specifications

Clinical Context

A typical patient is an adult referred to neurology for evaluation of fluctuating skeletal muscle weakness, ptosis, diplopia, or fatigable weakness that suggests a disorder of the neuromuscular junction such as myasthenia gravis or Lambert-Eaton myasthenic syndrome. The clinical workflow includes a focused history and neurologic exam, review of prior antibody testing (e.g., acetylcholine receptor or MuSK), and selection of target muscle(s) for testing. Repetitive nerve stimulation (RNS) is scheduled in an electromyography (EMG)/nerve conduction study (NCS) laboratory or outpatient neuromuscular clinic. The patient is positioned, skin prepared, and surface electrodes placed over the stimulating nerve and the target muscle. Baseline compound muscle action potentials (CMAPs) are recorded, then the nerve is stimulated repetitively at specified frequencies (commonly 2–5 Hz). The provider documents pre- and post-test CMAP amplitudes and decremental or incremental responses. Findings consistent with a significant decrement (typically ≥10% at low-rate stimulation) support a diagnosis of a neuromuscular junction disorder and guide further management, such as serologic testing, thymoma imaging, or medication adjustments. Typical site of service is an outpatient EMG/NCS laboratory, neurology clinic, or hospital neurophysiology lab. Service type is diagnostic electrodiagnostic testing specific to neuromuscular junction assessment.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when reporting only the physician interpretation and report separate from technical services provided by the facility or technologist.

CPT 95930: Visual Evoked Potential Testing

CPT-95938-SHORT-LATENCY-SSEP-UPPER-AND-LOWER-LIMBS

CPT 95938: Short‑Latency Somatosensory Evoked Potential Study

CPT-95929-CENTRAL-MOTOR-EVOKED-POTENTIAL-LOWER-LIMB

CPT 95929: Central Motor Evoked Potential Study for Lower Limbs

CPT-95927-SHORT-LATENCY-SOMATOSENSORY-EVOKED-POTENTIAL-STUDY

CPT 95927: Short-Latency Somatosensory Evoked Potential Study

CPT-95926-LOWER-LIMB-SHORT-LATENCY-SSEP

CPT 95926: Short-Latency Somatosensory Evoked Potential, Lower Limbs

CPT-95925-UPPER-LIMB-SOMATOSENSORY-EVOKED-POTENTIAL-SSEP

CPT 95925: Short‑Latency Somatosensory Evoked Potential, Upper Limbs

CPT-95939-CENTRAL-MOTOR-EVOKED-POTENTIAL-UPPER-LOWER-LIMBS

CPT 95939: Central Motor Evoked Potential Study, Upper and Lower Limbs

CPT-95928-CENTRAL-MOTOR-EVOKED-POTENTIAL-UPPER-LIMB

CPT 95928: Central Motor Evoked Potential Study for Upper Limb Muscles

CPT-95933-ORBICULARIS-OCULI-BLINK-REFLEX-ELECTRODIAGNOSTIC-TEST

CPT 95933: Orbicularis Oculi (Blink) Reflex Electrodiagnostic Test

Taxonomy Code	Specialty	Notes
207RH0000X	Neurology	Neurologists commonly perform and interpret EMG/NCS and RNS testing.
2084P0800X	Physical Medicine & Rehabilitation	PM&R physicians may perform electrodiagnostic studies in outpatient settings.
208000000X	Clinical Neurophysiology	Specialists focusing on diagnostic neurophysiology often perform advanced electrodiagnostic testing.
363L00000X	Physiatry (alternative)	Physicians in rehabilitation medicine with electrodiagnostic expertise may perform RNS.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`G70.00`	Myasthenia gravis without (acute) exacerbation	Primary diagnosis for which repetitive nerve stimulation is commonly performed to detect a decremental response at the neuromuscular junction.
`G70.01`	Myasthenia gravis with (acute) exacerbation	RNS helps document worsening neuromuscular transmission during an exacerbation and may guide urgent management.
`G70.81`	Lambert-Eaton myasthenic syndrome	RNS can demonstrate incremental responses at higher stimulation rates or post-exercise facilitation characteristic of presynaptic disorders.
`G73.9`	Disorder of nerve, unspecified	Used when specific peripheral or neuromuscular diagnosis is pending but junction testing is indicated in the diagnostic workup.
`R53.1`	Weakness	Symptom code often accompanying evaluation with RNS when focal or generalized fatigable weakness is reported.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`95886`	Needle electromyography, 1 extremity with or without related paraspinal areas; initial needle examination	Performed before or after RNS to assess muscle electrical activity and help localize neuromuscular vs. myopathic pathology.
`95885`	Needle electromyography, 1 extremity with or without related paraspinal areas; subsequent needle examination	Used for follow-up or additional needle EMG sampling in the same encounter when further evaluation is needed.
`95938`	Repetitive nerve stimulation testing, each additional muscle (List separately in addition to code for primary muscle)	Billed in addition to the primary RNS code when multiple muscles are tested during the same session.
`95905`	Nerve conduction, amplitude and latency/velocity study; peroneal motor and sural sensory, etc. (example of NCS codes)	Standard nerve conduction studies are often performed alongside RNS to evaluate peripheral nerve function and rule out neuropathy.
`99070`	Supplies and materials (noncovered)	May be used by facilities to account for disposable supplies used during electrodiagnostic testing.

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