Where this LCD applies
Each contract number is a jurisdiction on the remittance; the policy binds claims processed under these contracts and no others.
Billing and coding: diagnoses and procedure codes
Since 2019 the codes live in the companion article rather than the LCD. Billing and Coding A56773 (Billing and Coding: Neurophysiology Evoked Potentials (NEPs)) carries the diagnosis and procedure lists the contractor loads as the claims edit. CPT codes are shown as bare numbers because the descriptors are licensed by the AMA; HCPCS Level II descriptors are public and shown.
A56773: Billing and Coding: Neurophysiology Evoked Potentials (NEPs) (Billing and Coding, effective 2025-10-01)
- Covered ICD-10-CM codes
- 1653
- 3 groups
- Non-covered ICD-10-CM codes
- 1
- Procedure codes listed
- 11
- Full article
- cms.gov record
| ICD-10-CM | Description (FY2027) |
|---|---|
| A39.82 | — |
| A52.11 | — |
| A52.13 | — |
| A52.14 | — |
| A52.15 | — |
| A52.17 | — |
| A52.19 | — |
| A69.21 | — |
| A69.22 | — |
| A69.23 | — |
| A69.29 | — |
| A83.0 | — |
| A83.1 | — |
| A83.2 | — |
| A83.3 | — |
| A83.4 | — |
| A83.5 | — |
| A83.6 | — |
| A83.8 | — |
| A84.0 | — |
| A84.1 | — |
| A84.81 | — |
| A84.89 | — |
| A85.2 | — |
Procedure codes: 92651, 92652, 92653, 95925, 95926, 95927, 95928, 95929, 95930, 95938, 95939.
Coverage indications, limitations and medical necessity
Notice: It is not appropriate to bill Medicare for services that are not covered (as described by this entire LCD) as if they are covered. When billing for non-covered services, use the appropriate modifier.
Compliance with the provisions in this policy may be monitored and addressed through post payment data analysis and subsequent medical review audits.
History/Background and/or General Information
Neurophysiology Evoked Potentials (NEPs) for the purpose of this LCD include:
• Somatosensory Evoked Potentials/Responses (SEPs/SERs),
• Brainstem Auditory Evoked Potentials/Responses (BAEPs/BAERs), and
• Visual Evoked Potentials/Responses (VEPs/VERs)
Evoked potential studies are recorded electrical responses to stimulation of a sensory system. When a sensory impulse reaches the brain, a specific Electroencephalographic (EEG) response is produced (evoked) in the cortical area appropriate to the modality and site of the stimulus. By computer averaging techniques, the evoked responses of repetitive stimuli can be separated from the spontaneous EEG activity. Evoked potentials are clinically useful in evaluating the functional integrity of the somatosensory or special sensory pathways. Different latencies and wave patterns help to localize lesions ranging from the end organ through the nervous system to the cerebral cortex. Often defects in these pathways are not otherwise evident. Evoked potentials are also used to monitor neural pathways when patients are anesthetized during surgery and to document brain death. The following are tests that evaluate potentials evoked by stimulation of the peripheral or cranial nerves:
SEPs/SERs evaluate the pathways from nerves in the extremities through the spinal cord, to the brainstem or cerebral cortex upon stimulation of peripheral axon.
SEPs have an advantage in that it evaluates the entire somatosensory pathway and it is possible to distinguish between lesions located in the peripheral nerve, in the dorsal column pathway, or both.
VEPs/VERs evaluate the visual nervous system pathways from the eyes to the occipital cortex of the brain. VEP or VER involves stimulation of the retina and optic nerve with a shifting checkerboard pattern or flash method. This external visual stimulus causes measurable electrical activity in neurons within the visual pathways. This is called the Visual Evoked Response (VER) and is recorded by electroencephalography electrodes located over the occiput. Using special computer techniques, the evoked responses measured over multiple trials are amplified and averaged. A characteristic waveform is produced. With pattern-shift VER, the waveform normally appears as a straight line with a single positive peak (100 msec after stimulus presentation). Abnormalities in this characteristic waveform may be seen in a variety of pathologic processes involving the optic nerve and its radiations. Pattern-shift VER is a highly sensitive means of documenting lesions in the visual system. It is especially useful when the disease process is subclinical, e.g., ophthalmologic exam is normal and patient lacks visual symptoms.
BAEPs/BAERs evaluate the auditory nerve pathways from the ears through the brain stem. A clicking sound is presented to one ear at a time. The electrical activity of this signal is recorded by electrodes on the scalp. The averaged response is displayed as a waveform that contains peaks and troughs, which correspond to various points along the hearing pathway. The time between these peaks is measured and compared to normal data. A delay in a component of the response might indicate an abnormality at specific anatomic sites in the acoustic nerve or brainstem.
Covered Indications
Somatosensory Evoked Potentials and Responses (SEPs/SERs) are appropriate for the following indications:
• Spinal cord trauma
• Degenerative, non-traumatic spinal cord lesions (e.g., cervical spondylosis with myelopathy)
• Multiple sclerosis
• Spinocerebellar degeneration
• Myoclonus
• Coma
• Intraoperative monitoring
• Subacute combined degeneration
• Other diseases of myelin (e.g., adrenoleukodystrophy, adrenomyeloneuropathy, metachromatic leukodystrophy, and Pelizaeus-Merzbacher disease)
• Syringomyelia
• Hereditary spastic paraplegia
Brainstem Auditory Evoked Potentials and Responses (BAEPs/BAERs) are appropriate:
• For one or more of the following conditions:
• Asymmetric hearing loss
• Unilateral tinnitus
• Sudden hearing loss
• Cerebellopontine angle tumor
• Demyelinating disorder
• Functional hearing loss
• Ototoxic drug therapy monitoring including chemotherapy or antibiotics
• Auditory neuropathy
• Acoustic neuroma
• Preoperative baseline for:
• Posterior fossa surgery
• Cochlear implant
• Postoperative testing for:
• Cochlear implant
Note: Please refer to LCD L35007, Vestibular and Audiologic Function Studies for additional information regarding BAEPs/BAERs.
Visual Evoked Potentials or Responses (VEPs/VERs) are appropriate for the following indications:
• Confirm diagnosis of multiple sclerosis when clinical criteria are inconclusive.
• Detect optic neuritis at an early, subclinical stage.
• Evaluate diseases of the optic nerve, such as:
• Ischemic optic neuropathy
• Pseudotumor cerebri
• Toxic amblyopias
• Nutritional amblyopias
• Neoplasms compressing the anterior visual pathways
• Optic nerve injury or atrophy
• Hysterical blindness (to rule out)
• Monitor the visual system during optic nerve (or related) surgery (monitoring of short-latency evoked potential studies).
Limitations
The following are considered not reasonable and necessary and therefore will be denied:
• SEP studies are appropriate only when a detailed clinical history and neurologic examination and appropriate diagnostic tests such as imaging studies, electromyogram, and nerve conduction studies make a lesion (or lesions) of the central somatosensory pathways a likely and reasonable differential diagnostic possibility.
• There is no need for SEPs in the diagnosis of most neuropathies because the conventional nerve conduction study can identify them and no added information is obtained from SEPs.
Place of Services (POS)
For additional information on services performed in an Independent Diagnostic Testing Facility (IDTF), please refer to Local Coverage Determination (LCD) L35448 Independent Diagnostic Testing Facility (IDTF).
Provider Qualifications
Testing shall be performed by physicians who have evidence of training, and expertise to perform and interpret these tests. Physicians must have knowledge, training, and expertise to perform and interpret these tests, and to assess and train personnel working with them. This Training and expertise must have been acquired within the framework of an accredited school, residency or fellowship program.
Notice: Services performed for any given diagnosis must meet all of the indications and limitations stated in this policy, the general requirements for medical necessity as stated in CMS payment policy manuals, any and all existing CMS national coverage determinations, and all Medicare payments rules. Refer to Billing and Coding: Neurophysiology Evoked Potentials (NEPs), A56773, for applicable CPT/HCPCS codes and diagnosis codes.
The redetermination process may be utilized for consideration of services performed outside of the reasonable and necessary requirements in this LCD.
Summary of evidence (opening)
N/A
The contractor cites 17 sources in the bibliography; the full summary and analysis of evidence are in the CMS record.
Dates, lineage and related policies
- Original determination effective
- 2015-10-01
- Current revision effective
- 2019-10-17
- Last reviewed by the contractor
- 2018-09-05
- MCD version
- 67
- Derived from
- L32640
The contractor lists one National Coverage Determination as related: NCD 160.10 Evoked Response Tests. Where an NCD speaks, it controls; the LCD can only address what the NCD leaves open.
Using this policy on a claim
Match the documented indication to the covered indications above before the service is scheduled, carry a diagnosis from the article's covered list on the claim line, and keep the elements the documentation section asks for in the record, because the contractor can request it later through medical review. A denial under this policy arrives as CARC 50 with remark N115; the LCD lookup guide walks through the appeal path and the Advance Beneficiary Notice rules, and the Novitas Solutions, Inc. hub lists every other active policy from the same contractor.
Frequently asked questions
What does LCD L34975 cover?
Evoked potential studies are recorded electrical responses to stimulation of a sensory system. When a sensory impulse reaches the brain, a specific Electroencephalographic (EEG) response is produced (evoked) in the cortical area appropriate to the modality and site of the stimulus. By computer averaging techniques, the evoked responses of repetitive stimuli can be separated from the spontaneous EEG activity. Evoked… The full indications and limitations are reproduced on this page from the CMS Medicare Coverage Database export of September 24, 2026.
Which states does LCD L34975 apply to?
Novitas Solutions, Inc. applies it to Medicare claims in AR, CO, DC, DE, LA, MD, MS, NJ, NM, OK, PA, TX. A Local Coverage Determination binds only the contractor that wrote it; the same service in another jurisdiction is judged under that contractor's own policy or, where none exists, claim by claim.
Which diagnosis codes support medical necessity under LCD L34975?
The companion billing and coding article A56773 lists 1,653 ICD-10-CM codes in 3 groups that support medical necessity and 1 that do not; the first 24 appear on this page and the complete list is in the article on cms.gov.
How do I appeal a denial under LCD L34975?
The remittance carries claim adjustment reason code 50 with remark code N115, naming the LCD. Compare the documented indication with the policy's covered indications and the article's diagnosis list, then file a redetermination within 120 days with the record attached; if the service genuinely falls outside the policy, the patient can be billed only when a valid Advance Beneficiary Notice was obtained before the service.
Sources
Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-02. Verify against the primary file before billing or contracting decisions.
- Medicare Coverage Database, current LCD exportVersion MCD release 2026-09-24 · effective 2026-09-20 · file lcd.csvSHA-256 2fcc4251b6ddd1eb…
- Medicare Coverage Database, current Billing and Coding Articles exportVersion MCD release 2026-09-24 · effective 2026-09-20 · file article.csvSHA-256 f31932f1df3b4035…
- ICD-10-CM FY2027 code descriptionsVersion FY2027 · effective 2026-10-01 · file icd10cm_codes_2027.txtSHA-256 3c0583a38ee0e848…
Disclaimer
The policy text and code lists are reproduced from the CMS Medicare Coverage Database export as an operational reference. Verify against the current LCD and article on cms.gov before billing; coverage depends on the full record and the contractor. Not legal, clinical or billing advice.