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CurrentAetnaPolicy 0502

Electrodiagnostic Testing

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Defines Aetna's medical necessity, coverage limits, documentation and performance requirements for electrodiagnostic testing (NCS, EMG, neuromuscular junction testing, late responses, blink reflexes) for diagnosis and follow-up of neuromuscular disorders for Aetna members.

Policy Summary

PayerAetna

PolicyElectrodiagnostic Testing

Policy CodePolicy 0502

Change TypeNo material change

Effective DateApr 27, 2001

Last ReviewJul 29, 2026

Next Review DateMay 27, 2027

Key ActionSubmit a full on-site EDX report with demographics, referral reason, history/exam, tabulated NCS and EMG data, study limitations, probable diagnosis, and signature with timestamp.

SourceLink

2/yrEDX tests typical

3/yrMotor neuronopathy/plexopathy

AANEM 2025AANEM guidance source

Physician-onlyPhysician-performed EMG

95907-95913NCS CPT series

Coverage Criteria — Electrodiagnostic Testing (EDX)

General medical necessity indications

Aetna considers the following EDX tests medically necessary when criteria are met:

Primary indications: Member has any of: diagnosis or prognosis of traumatic nerve lesions; diagnosis and monitoring of neuromuscular junction disorders using repetitive nerve stimulation; diagnosis of muscle disorders (e.g., myopathy, myositis, muscular dystrophy); diagnosis or confirmation of suspected generalized neuropathies (e.g., Guillain–Barré syndrome, post‑polio syndrome, uremic/metabolic/immune neuropathies); differential diagnosis of unexplained sensory loss, weakness or muscle atrophy; differential diagnosis of symptom‑based complaints (pain, weakness, cramps, fasciculations, paresthesias) when clinical assessment supports the need for study; localization of focal neuropathies or compressive lesions (e.g., facial nerve palsy, carpal tunnel, cubital tunnel, tarsal tunnel, nerve root compression, plexopathy); unexplained peripheral neuropathy with demonstrated motor or sensory loss of unknown etiology.

See chunks 4-5 for full list.

Carpal tunnel disease-specific criteria

For individuals suspected of carpal tunnel syndrome, all applicable disease-specific criteria must be met:

CTS sensory and motor study requirements:

Policy Summary

PayerAetna

PolicyElectrodiagnostic Testing

Policy CodePolicy 0502

Change TypeNo material change

Effective DateApr 27, 2001

Last ReviewJul 29, 2026

Next Review DateMay 27, 2027

Key ActionSubmit a full on-site EDX report with demographics, referral reason, history/exam, tabulated NCS and EMG data, study limitations, probable diagnosis, and signature with timestamp.

SourceLink

On This Page

Sensory conduction studies across the wrist of the median nerve using a conduction distance of 13–14 cm; if results are abnormal, perform a sensory study of one other sensory nerve in the symptomatic limb; if the initial median sensory study across the wrist uses a conduction distance >8 cm and is within normal limits, one of the following additional comparative studies is medically necessary: (1) compare median sensory conduction across the wrist with radial or ulnar sensory conduction across the wrist in the same limb; or (2) compare median sensory or mixed nerve conduction with ulnar sensory conduction across a short (7–8 cm) conduction distance; or (3) compare median nerve conduction through the carpal tunnel to proximal or distal segments of the median nerve in the same limb; and motor conduction studies of the median nerve recording from the thenar muscle and of one other nerve in the symptomatic limb including measurement of distal latency.

Median sensory conduction across wrist distance 13-14 cm; CSI >= 0.9 ms considered abnormal

See chunk 5 for procedural criteria and chunk 55 for CSI context.

Radiculopathy criteria

For evaluation of cervical, thoracic or lumbar radiculopathy, all of the following must be met:

Radiculopathy preconditions: Persistent or progressive symptoms; failed non‑surgical medical management with at least 6 weeks of formal in‑person physical therapy in the past year (confirmed by PT notes or member claims); and symptoms unexplained by imaging studies (e.g., MRI, myelogram).

See chunk 6 for required preconditions; documentation of PT required per chunk 8.

Distal symmetric polyneuropathy (DSP) indications

For suspected distal symmetric polyneuropathy (DSP), any of the following criteria justify EDX:

DSP indications: No identified etiology after history, physical exam and standard neuropathy blood tests (e.g., CBC, CMP, B12, SPEP with immunofixation, fasting glucose and glucose tolerance); or symptoms and/or physical findings are moderate to severe; or an atypical presentation (motor predominance, asymmetry or proximal deficits); or rapid progression of symptoms or signs; or discrepancy between signs and symptoms; or history of exposure to medications or toxins known to cause neuropathy; or family history suggesting hereditary neuropathy; or overlapping signs suggesting another diagnosis (e.g., radiculopathy).

See chunks 6, 58, 59 for recommended laboratory evaluation and indications.

EMG and NCS performance and exceptions

Requirements for concurrent EMG and NCS and performer qualifications:

EMG with NCS: Needle EMG performed concurrently with NCS is medically necessary when applicable NCS criteria are met; the requirement for concurrent EMG may be waived for persons with coagulation disorders or on anticoagulant therapy that cannot be interrupted; unless an approvable exception is documented, NCS cannot be approved without an approvable EMG request.

See chunk 7.

Personnel and reporting: NCS and EMG must be performed by a physician trained in electrodiagnostic medicine or by a resident/fellow under direct supervision with real‑time interpretation by an EDX‑trained physician; only physicians should perform needle insertion portions; technologists may perform NCS only. Testing must be performed, reported and interpreted on‑site in real time and a full EDX report including data summary tables should be submitted.

See chunk 8 for on‑site reporting and performer qualifications.

Medical necessity and procedural requirements

Covered when ALL applicable policy requirements and selection criteria are met for the specific test and clinical indication

Basic test performance and reporting: Testing must be individualized to the patient's anatomy and diagnostic question; waveforms should be reviewed and technique adjusted on site; reports prepared on site must include interpretation, NCV calculations, comparison to normal values, clinical summary, differential diagnosis and recommendations.

See chunk 35 for performance and reporting expectations.

Modality selection: NCS, EMG, late responses (F‑wave, H‑reflex), neuromuscular junction testing (repetitive stimulation) and blink reflex studies are covered when selected tests address the diagnostic question; specialized components are covered when clinically indicated.

See chunks 31 and 30 for modality specifics.

Use of automated devices: Automated/point‑of‑care NCS devices do not supplement, replace or duplicate standard NCS; standard testing by trained clinicians is required for comprehensive evaluation and interpretation.

See chunk 36 regarding limitations of automated devices.

Quantity limits: Number of limbs studied by EMG and total nerves studied by NCS should align with the per‑condition examples and limits provided in the policy; exceeding those limits may require prior authorization or supplemental justification.

See chunks 23-26 for per‑diagnosis examples and limits.

Appropriate use considerations

EDX testing is clinically appropriate in the following scenarios:

Indications for EDX: Consider EDX when standard evaluation does not indicate a likely etiology, or when symptoms are moderate to severe, or when presentation is atypical or rapidly progressive.

See chunk 59 and 58 for AANEM and DSP guidance.

DSP evaluation labs: In DSP without a known cause, obtain routine laboratory testing (CBC, CMP, B12, SPEP with immunofixation, fasting glucose and glucose tolerance) prior to or concurrent with EDX.

See chunk 58 for recommended laboratory screening.

Point‑of‑care NCS use: Portable automated sural NCS (e.g., NC‑stat DPNCheck) may be used as a screening tool; abnormal or inconclusive results should prompt standard NCS and clinical correlation.

See chunk 61 describing device performance and chunk 36 for limitations.

Carpal tunnel CSI: Combined Sensory Index (CSI) may increase diagnostic sensitivity for CTS when standard NCS are equivocal; a CSI ≥ 0.9 ms is considered abnormal, though guideline endorsement by name is limited.CSI >= 0.9 ms

See chunk 55 for CSI performance and threshold.

Cubital tunnel assessment: Short‑segment nerve conduction studies can detect focal ulnar nerve lesions more sensitively than routine motor NCS; CMAP amplitude reductions better predict functional impairment than conduction velocity alone and can inform prognosis and timing of intervention.

See chunk 72 for evidence on CMAP amplitude in Cubital Tunnel Syndrome.

Aetna considers specific devices, systems and several applications to be experimental, investigational, or unproven. Examples include the Cadwell Sierra II system, ADVANCE NCS/EMG System, Brevio NCS monitor, NC-stat DPNCheck and other automated or hand‑held NCS devices, as well as specific uses such as the F‑wave study for carpal tunnel syndrome, phrenic nerve conduction testing for lung transplant evaluation, NCS for COVID‑19‑associated neuromuscular disorders, and routine NCS for screening or monitoring diabetic or ESRD polyneuropathy. These devices and applications lack sufficient evidence of established clinical effectiveness to be covered.

The policy lists certain ICD‑10 diagnoses for which NCS/EDX testing is not covered for the indicated uses. Examples include D51.0–D51.9 (vitamin B12 deficiency anemia), E08.00–E13.9 (diabetes mellitus) for screening/monitoring indications, and other specified systemic or chronic conditions noted in the CPT/ICD tables. Providers should confirm that the requested indication matches a covered diagnosis and the policy's selection criteria before ordering testing.

Nerve conduction studies performed in isolation, without concurrent needle EMG and without integration of the clinical history and physical exam, may be inadequate to establish a diagnosis. The AANEM and this policy note that NCS alone provides only part of the information needed for many muscle, root and nerve disorders; unless an approvable exception is documented, NCS cannot be approved without an approvable EMG request.

Point‑of‑care and other automated devices (e.g., NC‑stat DPNCheck, Brevio, ADVANCE systems) have intrinsic limitations: they generally test a restricted set of distal nerves, use pre‑set stimulation/recording sites, and produce computer‑generated interpretations. These limitations mean such devices do not supplement, replace, or duplicate comprehensive standard NCS performed and interpreted by trained clinicians, and their results should be correlated with clinical findings and standard NCS when indicated.

Nerve conduction studies have no role in the routine workup of Peyronie’s disease; major guideline sources (AUA) and clinical reviews (UpToDate) provide no recommendation supporting NCS for this indication.

There is no current role for using nerve conduction velocity studies to follow disease progression in spinal muscular atrophy (SMA); the routine use of NCV for monitoring SMA is not supported and assessment of motor unit function for treatment response remains investigational.

When billing EMG performed on the same day as NCS, physicians must use the appropriate add‑on EMG codes (CPT 95885–95887). These codes are add‑on only and may not be billed independently of a qualifying NCS code; documentation should support the number of extremities and muscles tested and meet the policy's requirements for a limited versus complete EMG.

This Clinical Policy Bulletin is intended to assist in administering plan benefits and provides general information about coverage criteria and documentation expectations; it does not constitute a contract, is not medical advice, and does not guarantee coverage for individual members or claims.

Screening for neuropathy using NCS is considered experimental, investigational, or not medically necessary when symptoms and exam findings are mild, primarily sensory, and a cause is already known. Routine screening NCS for diabetic or end‑stage renal disease patients without qualifying clinical features is not supported by this policy.

Automated and point‑of‑care NCS devices do not meet the policy's standards for a comprehensive NCS because they test a limited set of nerves, use pre‑determined techniques, and rely on automated scoring. As such, they do not satisfy requirements for full standard NCS performance and interpretation by trained clinicians and are considered limited in role.

Hand‑held automated NCS devices (examples: NC‑Stat, Brevio, Nervepace) lack sufficient evidence demonstrating diagnostic equivalence to standard clinician‑performed NCS/EMG. Studies show that while raw recordings may be comparable, automated device interpretations can be overly sensitive with reduced specificity; therefore these devices do not have established equivalence to standard testing for routine diagnostic use.

The policy explicitly states that NCV studies are not supported for routine monitoring of spinal muscular atrophy progression; use of NCV for this purpose currently has no established role.

Coding — CPT/ICD and Related Codes

EDX / NCS CPT guidanceCPT

95907-95913

CPT descriptor language describes one or more NCSs

Nerve Conduction Velocity Studies (covered if criteria met)CPTCovered

95907	Nerve conduction studies; 1-2 studies.
95908	3-4 studies.
95909	5-6 studies.
95910	7-8 studies.
95911	9-10 studies.
95912	11-12 studies.
95913	13 or more studies.
95905	Motor and/or sensory nerve conduction, using preconfigured electrode array(s), amplitude and latency/velocity study, each limb, includes F-wave study when performed, with interpretation and report.

Electromyography CPT CodesCPTCovered

95860	Electromyography.
95861	Electromyography.
95862	Electromyography.
95863	Electromyography.
95864	Electromyography.
95867	Electromyography.
95868	Electromyography.
95869	Electromyography.
95870	Electromyography.
95885	Electromyography.

1–10 of 12

1/2

Neuromuscular Junction TestingCPTCovered

95937

Neuromuscular junction testing (repetitive stimulation, paired stimuli), each nerve, any 1 method.

Blink ReflexesCPTCovered

95933

Orbicularis oculi (blink) reflex, by electrodiagnostic testing.

Selected ICD-10 codes (covered or not covered per policy lists)ICD-10

G56.00 - G56.03	Carpal tunnel syndrome [not covered for F-wave (F‑reflex) study].
G61.0 – G62.82	Polyneuropathies.
G70.00 - G70.01	Myasthenia gravis and myasthenic syndromes in disease classified elsewhere.
G70.80 - G70.89	Lambert‑Eaton syndrome.
G12.21	Amyotrophic lateral sclerosis.
D51.0-D51.9	Vitamin B12 deficiency anemia (listed as ICD-10 codes not covered for indications in the CPB).
E08.00-E13.9	Diabetes Mellitus (listed as ICD-10 codes not covered for indications in the CPB).

Other related CPT/NDC/lab codes referencedmixed

82607	Cyanocobalamin (Vitamin B-12).
82608	Cyanocobalamin (Vitamin B-12); unsaturated binding capacity.
82947	Glucose; quantitative, blood (except reagent strip).
83036	Hemoglobin; glycosylated (A1C).
84155	Protein, total; serum, plasma or whole blood.
86334	Immunofixation electrophoresis; serum.
97010-97799	Physical Therapy codes.

No explicit CPT/ICD codes listed in these chunksmixed

No codes listed

EMG codes when NCS performed same dayCPT

95885	EMG - limited study; billed in units per limb when NCS performed same day (add-on)
95886	EMG - complete study of limb; billed in units per limb when NCS performed same day (add-on)
95887	EMG - non-extremity study (e.g., cranial nerve muscles, diaphragm, paraspinals) when NCS performed same day (add-on)

EMG codes when NCS not performed same dayCPT

95860	Needle EMG, complete, 1 extremity
95861	Needle EMG, complete, 2 extremities
95863	Needle EMG, complete, 3 extremities
95864	Needle EMG, complete, 4 extremities
95870	Needle EMG, limited study
95865	EMG - larynx
95866	EMG - hemidiaphragm
95867	EMG - unilateral cranial nerve-supplied muscles
95868	EMG - bilateral cranial nerve-supplied muscles
95869	EMG - thoracic paraspinals

Codes cross-referenced to other CPBsmixed

95907	NCS code referenced for intraoperative neurophysiological monitoring
95861	See CPB 0697 - Intraoperative Neurophysiological Monitoring (cross-reference)
95865	See CPB 0697 - Intraoperative Neurophysiological Monitoring (cross-reference)
95866	See CPB 0697 - Intraoperative Neurophysiological Monitoring (cross-reference)

Median sensory conduction across wrist distance for CTS testing

Recommended conduction distance13–14 cm across the wrist for median sensory conduction studies

Follow-up when initial distance >8 cmIf initial median sensory study across the wrist >8 cm and normal, obtain an additional comparative study (median vs radial/ulnar or short-segment median comparison or proximal/distal median comparison)

Additional sensory testing when abnormalIf median sensory study is abnormal, perform sensory study of one other sensory nerve in the symptomatic limb

Per-diagnosis limbs studied / total nerves (examples)

Carpal tunnel (unilateral)EMG limbs studied = 1; NCS total nerves = 7

Carpal tunnel (bilateral)EMG limbs studied = 2; NCS total nerves = 10

RadiculopathyEMG limbs studied = 2; NCS total nerves = 7

Polyneuropathy/Mononeuropathy multiplexEMG limbs studied = 3; NCS total nerves = 10

PlexopathyEMG limbs studied = 2; NCS total nerves = 12

Combined Sensory Index abnormal threshold

CSI abnormal thresholdCombined Sensory Index (CSI) ≥ 0.9 ms is considered abnormal

CSI componentsSum of three sensory latency differences: median–ulnar (ring finger), median–radial (thumb), median–ulnar (midpalmar)

Clinical performanceReported sensitivity up to 94% in a prospective study when used with other NCS parameters

CSI abnormal threshold (duplicate entry)

CSI abnormal threshold (duplicate)Combined Sensory Index (CSI) ≥ 0.9 ms is considered abnormal

Also known asRobinson Index (sum of three sensory latency differences)

Evidence noteModest evidence base; not specifically endorsed by major society guidelines by name

Complete limb EMG threshold

Complete limb EMG definitionA complete study of a limb should include at least 5 muscles innervated by 3 or more peripheral nerves (or 4 or more spinal levels)

Billing contextWhen NCS is performed same day, use add-on EMG codes (95885–95887) billed in units per extremity

Paraspinal exceptionComplete study may be billed without paraspinal muscles if contraindicated or not feasible with documentation

F-wave responses minimum number

Minimum F‑wave responsesObtain at least 10 F‑wave responses when performing F‑wave studies

Technique noteF‑wave testing uses separate stimulation and settings from motor NCV and may be performed on some motor NCV studies but not others

IndicationF‑waves assess more proximal nerve segments and can aid evaluation of radiculopathies, plexopathies, and proximal mononeuropathies

Provider Actions — Documentation, Prior Authorization, and Billing

Prior Authorization

Case review required for excess studies

Requests that deviate from the policy's Maximum Number of Studies Table or established norms for the quantity and variety of procedures are subject to case review and require additional documentation and physician review when exceeding typical annual limits.

Case review expected when there is deviation from established norms for quantity and variety of procedures (Maximum Number of Studies Table).
Physician review and supplemental documentation required for studies beyond generally accepted amounts.

Prior Authorization

Follow per-diagnosis frequency and number limits

Frequency and allowable number of EDX studies per diagnosis are specified (per-condition limits for limbs studied by EMG and total nerves studied by NCS); exceeding these per-diagnosis limits may require prior authorization or justification.

Use the per-condition limbs/studies limits (e.g., carpal tunnel unilateral NCS total = 7; radiculopathy NCS total = 7) when planning testing.
Prior authorization may be required when recommended numbers are exceeded.

Denial Risk

Provide supplemental documentation / expect peer review for high-volume testing

When testing exceeds recommended limits or usage norms (for example approaching/exceeding the 90th percentile), provide supplemental documentation justifying additional tests and expect possible peer review.

Document clinical rationale and differential diagnoses that necessitate extra studies.
Supplemental physician justification should accompany requests above typical limits.

Note

Obtain EDX for specified clinical triggers

Obtain EDX testing when standard evaluation does not indicate a likely etiology, when symptoms are moderate to severe, or when presentation is atypical or rapidly progressive; tailor testing to the individual clinical question.

Consider EDX after history and exam when imaging or routine workup are non-diagnostic.
EDX is appropriate for moderate/severe symptoms, atypical features, or rapid progression.

Prior Authorization

Prior authorization — none explicitly required

No explicit prior authorization requirement is stated in these document sections; however, requests exceeding established study norms are subject to case review and may need additional documentation.

Prior authorization is not explicitly required by the policy text in these chunks.
Case review applies when utilization deviates from norms (see Maximum Number of Studies Table).

Billing Rule

Link EMG billing to same-day NCS status

Bill EMG CPT codes based on whether NCS is performed the same day: when NCS is same-day, use add-on codes 95885–95887 (per limb units); when NCS is not same-day, use primary EMG codes 95860–95864, 95870, or the relevant non‑extremity codes.

95885–95887 are add-on codes billed per limb and may not be billed independently when NCS is performed same day.
Use 95860–95864, 95870 or 95865–95869 when NCS is not performed same day.

Prior Authorization

Prior authorization — no explicit requirement stated

No explicit prior authorization requirements are stated in these document sections; clinical documentation should support medical necessity consistent with the CPB.

Documentation must support medical necessity even when prior authorization is not explicitly required.
Refer to case review rules for instances of high utilization or deviation from norms.

Documentation Required

Document failed non-surgical management and PT for radiculopathy

For evaluation of radiculopathy, document failed non-surgical medical management including at least 6 weeks of in-person formal physical therapy within the past year; PT must be confirmed by PT notes or member claims history.

PT must be in-person (not home or virtual) for at least 6 weeks in the past year.
Confirm PT with actual PT notes or documentation in member claims history.

Step Therapy

Limit use of automated NCS devices; obtain standard NCS when indicated

Automated or point-of-care NCS devices are limited and do not replace standard NCS performed by trained clinicians; use automated devices only for screening and correlate with standard NCS when results are abnormal or inconclusive.

Automated devices perform limited distal-only testing and lack on-site EMG integration.
Abnormal or inconclusive automated device results should prompt standard NCS and clinical correlation.

Step Therapy

Preoperative CTS testing should be within 12 months

For patients undergoing carpal tunnel release, ensure electrodiagnostic testing was performed within 12 months prior to surgery unless medical, patient, or system exceptions apply.

Preoperative EDX within 12 months is recommended to confirm diagnosis and assess severity.
Document any applicable exceptions if testing falls outside the 12‑month window.

Step Therapy

Obtain routine labs before advanced DSP testing

Before advanced testing for suspected distal symmetric polyneuropathy (DSP) of unknown cause, obtain routine laboratory screening including CBC, CMP, vitamin B12, serum protein electrophoresis with immunofixation, fasting glucose and glucose tolerance testing.

Order CBC, comprehensive metabolic panel, B12, SPEP with immunofixation, fasting glucose and glucose tolerance test prior to or concurrent with EDX.
Reserve EDX for cases where routine testing does not identify an etiology or when clinical features warrant electrophysiologic study.

Note

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Documentation Required

Submit full EDX report and consider attaching waveforms

Submit a full EDX report that includes all tests performed with tabulated NCS and EMG data; forwarding NCS waveforms is encouraged to support interpretation.

Include data summary tables for NCS (temperature, type, side/nerve, stimulation/recording sites, amplitudes, latencies, conduction velocities, reference values).
Include EMG data (side, muscles tested, activity data at rest and with activation), probable diagnosis/location, study limitations, prior study information, and signature with time stamp.

Documentation Required

Attach PT documentation to show prior treatment failure for radiculopathy

For radiculopathy, confirm prior physical therapy failure with PT notes or member claims history when submitting EDX requests; include documentation of prior treatments.

PT documentation must reflect at least 6 weeks of in-person therapy within the past year.
Attach PT notes or claims history to support medical necessity for EDX.

Documentation Required

Prepare and sign on-site EDX reports with full interpretation

Reports must be prepared on-site by the examiner and include interpretation, NCV calculations (and F‑wave indices when performed), comparison to normal values, clinical summary, differential diagnosis, and documentation of waveform review and technique adjustments during the encounter.

Ensure on-site, real-time review of waveforms and record technique adjustments in the report.
Include clinical summary, probable diagnosis/location, study limitations, and physician interpretation.

Documentation Required

Provide supplemental justification when testing exceeds limits

When testing exceeds recommended limits, provide supplemental documentation that explains the clinical rationale, differential diagnoses considered, study design and duration (typically ≥30 minutes), and why additional tests were necessary.

Document why extra studies were required and any changes in working diagnosis during the encounter.
Include study duration and technical details supporting expanded testing.

Documentation Required

Document point-of-care sural NCS results and limitations

When a point-of-care automated sural NCS device (e.g., NC-stat DPNCheck) is used, document device results, device limitations, and correlate findings with clinical examination; abnormal or inconclusive results should prompt standard NCS.

Record device-measured SNAP/SNCV values and note that POC devices may rule out neuropathy but do not confirm definitive diagnosis alone.
If results are abnormal or inconsistent with clinical findings, obtain standard NCS and include correlation in the report.

Documentation Required

Include required elements in the EDX report

EDX reports must include patient demographics, reason for referral, history and physical exam description, detailed tabulated NCS and EMG findings, study limitations, probable diagnosis and location, prior study information, and a signature with time stamp.

Provide tabulated NCS data (temperature, study type, side/nerve, recording/stimulation sites, amplitudes, latencies, conduction velocities, reference values).
Include EMG side/muscles tested and activity data (rest and voluntary activation) and a clear probable diagnosis.

Documentation Required

Ensure completeness of EDX report elements

EDX reports should be complete and include the full set of required elements (demographics, referral reason, history/exam, tabulated NCS/EMG data, study limitations, probable diagnosis, prior study info, and signature with time stamp) to avoid administrative rejection or denial.

Prefer tabular format for NCS and EMG data rather than narrative.
Ensure signature with time stamp is present on the report.

Documentation Required

Document medical necessity per CPB

Providers are responsible for documenting and supporting medical necessity consistent with Aetna Clinical Policy Bulletins; include sufficient clinical information to justify testing and treatment decisions.

Clinical documentation should align with CPB criteria for the requested EDX tests.
Maintain records that support the choice and extent of testing performed.

Denial Risk

Do not request NCS without an approvable EMG request unless exception documented

NCS will not be approved without an approvable EMG request unless a documented approvable exception exists; NCS and EMG utilization may be subject to case review when deviating from established norms.

Document any exceptions (e.g., coagulopathy) that waive the EMG requirement.
Expect case review when utilization deviates from the Maximum Number of Studies Table.

Denial Risk

Avoid coding/indication mismatches

Using CPT codes that are not within the covered code sets or coding tests for indications that do not meet the policy's selection criteria may trigger denial; ensure coding matches the documented clinical indication.

Select CPT codes consistent with the diagnosis and the policy's covered code lists.
Do not bill EMG add-on codes independently of an appropriate NCS code when required.

Denial Risk

High utilization may prompt peer review and denial risk

Testing utilization that significantly exceeds established norms (for example above the 90th percentile) may prompt peer review and could result in denial or require supplemental justification.

High utilization should be justified with clinical rationale and documented differential diagnoses.
Peer review mechanisms may be implemented for outlier providers or cases.

Note

Normal NCS does not exclude surgical benefit for ulnar nerve; pursue further testing if abnormal

Normal NCS findings do not necessarily preclude benefit from ulnar nerve decompression; if ulnar sensory or motor NCSs are abnormal, perform additional NCSs to exclude a diffuse process per AANEM guidance.

If ulnar NCS are abnormal, obtain further studies to rule out diffuse neuropathy.
Recognize that patients with clinical ulnar nerve compression may still benefit from surgery despite normal NCS.

Documentation Required

EDX report must contain all required elements

Ensure EDX reports are complete and include all required elements (demographics, referral reason, history/exam, tabulated NCS/EMG data, study limitations, probable diagnosis, prior study info, signature with time stamp) to support medical necessity and avoid administrative issues.

Prefer tabular presentation of NCS and EMG data and include reference values and limb temperatures.
Include study limitations and prior study comparisons where relevant.

Documentation Required

Document paraspinal rationale and number of muscles tested to avoid coding risks

If paraspinal muscles are not assessed when clinically indicated, document the rationale; also document the number of muscles tested since failure to do so may lead to incorrect billing or denial—EMG add-on codes may not be billed independent of an NCS code.

When a complete limb study omits paraspinals for contraindication, document the reason.
Record the number of muscles tested to justify the billed EMG code group.

Note

Administrative note: CPB use and potential plan effects

Clinical Policy Bulletins are intended to assist in administering plan benefits and do not constitute a contract; lack of adherence to published clinical policy may affect coverage determinations.

Providers remain responsible for medical advice and treatment; CPBs guide benefit administration but are not guarantees of coverage.
Policies may be updated; verify current policy at time of service.

Documentation Required

EDX report submission requirements and encouraged attachments

Submit a full EDX report including all tests performed with tabulated data and consider attaching NCS waveforms; the report should contain demographics, reason for referral, history/exam, tabulated NCS and EMG findings, probable diagnosis, study limitations, prior study info, and signature with time stamp.

Forwarding NCS waveforms is encouraged to support interpretations.
Prefer tabular formats for both NCS and EMG data and include limb temperatures and reference values.

Background — Scope and Definitions

Scope: Electrodiagnostic testing (EDX) in this policy encompasses nerve conduction studies (NCS), needle and single‑fiber electromyography (EMG), neuromuscular junction testing (e.g., repetitive stimulation), late responses (F‑wave, H‑reflex), and blink reflex studies. The policy defines medical necessity criteria, performance and reporting requirements, documentation expectations, and per‑condition testing limits to guide diagnosis and follow‑up of neuromuscular disorders.

Single NCS definition for coding

Single NCS coding definitionFor coding purposes, a single conduction study is a sensory conduction test, a motor conduction test (with or without an F‑wave), or an H‑reflex test as listed in the CPT 'Electrodiagnostic Medicine Listing'

Billing unit guidanceEach listed nerve line in the CPT appendix represents a separate billable unit; bilateral nerves are billed separately when tested

Inching not separate unitIt is inappropriate to bill more than one unit for 'inching' or studying the same nerve by moving the stimulating electrode

Nerve conduction studies (NCS) definition

What NCS measuresNerve conduction studies (NCS) measure conduction velocity (NCV), latency and amplitude of peripheral nerve responses to electrical stimulation

Modalities includedIncludes motor and sensory studies and late responses (H‑reflex, F‑wave) to assess proximal segments

Typical performanceUsually performed with surface electrodes; needle electrodes may be used for deep nerves or in obese patients

Electromyography (EMG) definition

EMG definitionElectromyography (EMG) uses needle electrode recordings of muscle electrical activity at rest and during contraction to detect denervation, reinnervation, or primary muscle disease

PurposeIdentifies neurogenic versus myopathic processes and helps localize lesions

Performed byPerformed by physicians specially trained in electrodiagnostics

Neuromuscular junction testing definition

Neuromuscular junction testingRepetitive stimulation or paired stimuli testing (CPT 95937) to evaluate disorders of neuromuscular transmission such as myasthenia gravis or Lambert‑Eaton syndrome

CodeCPT 95937 (each nerve, any one method)

Clinical useUsed when clinical presentation suggests a transmission disorder; often complementary to NCS/EMG

Blink reflex definition

Blink reflex definitionAn electrodiagnostic analog of the corneal reflex; latencies and side‑to‑side differences help localize pathology to cranial nerves V or VII or the brainstem

CPT codeOrbicularis oculi (blink) reflex testing — CPT 95933

Adjunct evaluationDetermine directly elicited facial motor responses to exclude peripheral facial abnormalities when blink reflexes are abnormal

Automated/point-of-care NCS devices definition

Automated/POC NCS devicesHand‑held or office devices that perform limited, typically distal‑only, nerve conduction tests using preset stimulation/recording sites (examples: NC‑Stat, Brevio, ADVANCE NCS/EMG)

LimitationsAutomated devices test specific distal sites only, use pre‑determined techniques, often lack EMG capability, and are usually performed by office staff rather than specialists

Policy stanceAutomated/POC devices do not replace standard NCS and are considered limited for comprehensive EDX evaluation

Combined Sensory Index (CSI) definition

CSI definitionCombined Sensory Index (CSI) sums three sensory latency differences (median‑ulnar ring finger, median‑radial thumb, median‑ulnar midpalmar)

Abnormal thresholdCSI ≥ 0.9 ms considered abnormal for CTS diagnosis

Alternate nameAlso known as the Robinson Index

Combined Sensory Index (CSI) duplicate definition

CSI definition (duplicate)The CSI is the sum of three sensory latency differences (median‑ulnar ring finger; median‑radial thumb; median‑ulnar midpalmar)

Diagnostic noteHas shown high sensitivity in some studies but remains modest in evidence volume and not explicitly named in major guidelines

Abnormal cutoffCSI ≥ 0.9 ms

NC-stat DPNCheck definition

NC‑stat DPNCheck descriptionA portable automated point‑of‑care device that measures sural sensory nerve conduction velocity and amplitude for screening/diagnosis of diabetic polyneuropathy

Performance in studyReported sensitivity 90.48% and specificity 86.11% for diagnosis of clinical DPN in one study

Policy positionMay be useful as a screening tool; abnormal or inconclusive results should prompt standard NCS and clinical correlation

CMAP amplitude definition

CMAP amplitude definitionCompound muscle action potential (CMAP) amplitude is the summated electrical response of muscle to motor nerve stimulation; reductions indicate axonal loss

Clinical relevanceReduced CMAP amplitude may better predict functional impairment (e.g., grip/pinch strength) than conduction velocity alone in Cubital Tunnel Syndrome

Use in prognosisConsider CMAP amplitude when counseling prognosis and timing of operative intervention

Late responses (F-wave, H-reflex) definition

Late responses overviewLate responses (F‑wave, H‑reflex) assess conduction in proximal nerve segments and nerve roots and are useful for radiculopathies, plexopathies, polyneuropathies, and proximal mononeuropathies

Complementary testingMotor and sensory NCS and late responses are often complementary and performed during the same evaluation

Potential sole abnormalityIn some cases, late responses may be the only abnormal study

Surface EMG (sEMG) definition

Surface EMG (sEMG)Noninvasive recording of skeletal muscle electrical activity using skin sensors; needle electrodes may be used when deeper evaluation is required

Typical useSurface electrodes are usually employed for stimulation and recording due to reproducibility and ease of use

When needle neededNeedle electrodes used for deep nerves or in extremely obese individuals

F-wave definition (recommended responses)

F‑wave recommendationObtain at least 10 F‑wave responses; separate stimulation and machine settings from motor NCV are used to collect multiple responses

Indication variabilityNumber of F‑wave studies depends on working diagnosis and other electrodiagnostic findings; some motor NCV studies may include an F‑wave while others do not

PurposeAssesses more proximal nerve segments and can aid evaluation of radiculopathies, plexopathies, and proximal mononeuropathies

H-reflex definition and typical study count

H‑reflex definitionAn H‑reflex study records a reflexive discharge from muscle after nerve stimulation to assess conduction between limb and spinal cord

Typical study countTypically only 2 H‑reflex studies are performed in a given examination and usually performed bilaterally

Common muscleOften assessed in the gastrocnemius/soleus complex to evaluate S1/root level pathology; may be used in upper limb (flexor carpi radialis) rarely

Blink reflex definition (appendix)

Blink reflex (appendix)The blink reflex is an electrodiagnostic analog of the corneal reflex; latency and side‑to‑side differences help localize pathology to CN V or VII or the brainstem

Clinical actionIf blink reflexes are abnormal, determine facial motor responses to exclude peripheral abnormality

UtilityUseful in diagnosing cranial neuropathies or central lesions

Clinical Policy Bulletin definition and disclaimer

Clinical Policy Bulletin purposeClinical Policy Bulletins assist in administering plan benefits and do not constitute medical advice or guarantees of coverage

Not a contractThe CPB provides a partial, general description of plan benefits and is not an explicit coverage guarantee

Review datesLast review 07/29/2026; Effective date 04/27/2001; Next review 05/27/2027