Model Policy for Nerve Conduction Studies and Needle Electromyography
The electrodiagnostic (EDX) evaluation is an extension of the neuromuscular portion of the physical examination and requires a detailed knowledge of a patient and their disease. During an EDX evaluation, physicians typically perform nerve conduction studies (NCSs) and needle electromyography (EMG).
EDX evaluations are performed by physicians, almost exclusively neurologists or physiatrists. Training to perform these procedures should occur in conjunction with training in the clinical diagnostic and management aspects of neuromuscular disease. This training allows for the proper performance of an EDX evaluation and the correct interpretation of EDX test results. Physicians performing an EDX evaluation must be aware of the patterns of abnormality observed in different diseases. Physicians must also be able to interpret the results of NCSs and needle EMG and combine these results with the patient’s history, physical examination, and other test results to reach a diagnosis. EDX results may be similar in different diseases therefore a thorough knowledge of EDX evaluation is important to assure quality patient care. Non-physician providers, including physical therapists, chiropractors, physician assistants, and others, do not have the appropriate training and knowledge to perform and interpret EMG studies and interpret NCSs. These providers, along with appropriately trained and supervised technologists, may perform NCS with direct physician supervision.
Both EMGs and NCSs are usually required for a clinical diagnosis of peripheral nervous system disorders. Performance of one test does not eliminate the need for the other. The number of EMG and NCSs needed to determine a diagnosis are matters of clinical judgment. The complexity and extent of testing needed is determined after the initial pre-test evaluation and often modified during the testing procedure. NCSs may be performed without EMG on some occasions, e.g., entrapment neuropathies, but this should be the exception rather than the normal practice pattern.
Decisions to continue, modify, or conclude an EDX study rely on knowledge of anatomy, physiology, and neuromuscular diseases. Ongoing real-time assessment of data is required during the clinical diagnostic evaluation and especially during the needle EMG examination. The EDX physician is integrally involved in performing and interpreting the needle EMGs as the study progresses. A needle EMG may not be performed at one time and “read” at another time; the diagnostic decision-making is simultaneous with performance.
After conducting a history and physical examination, the EDX physician develops a working diagnosis that may modify the referral diagnosis. The EDX physician’s working diagnosis also may be modified as the EDX evaluation proceeds. A number of tests may be needed to address the referral and working diagnoses and to arrive at the correct final diagnosis. Other diagnoses are often considered during testing, the final diagnosis therefore may not accurately reflect all the decisions made throughout the testing process or all the work the physician performed to reach the final diagnosis. EDX testing does not always establish an etiologic diagnosis. When “rule-out” diagnoses are not accepted, only a symptomatic diagnosis (e.g., ICD-10-CM codes M79.601-M79.676 “pain in limb” or R20.0-R20.9 “disturbance in skin sensation”) can be coded, regardless of the work involved in performing the EDX examination.
EDX testing is used to evaluate the integrity and function of the peripheral nervous system (most cranial nerves, spinal roots, plexi, and nerves, neuromuscular junction, muscles) and its connection with the central nervous system.
A typical EDX examination includes the following:
Indications for EDX testing include the following scenarios:
Nerve Conduction Studies
Late Responses: H-Reflex and F-Wave Studies
Nerve Conduction Studies
EDX testing with automated, noninvasive nerve conduction testing devices is considered investigational and not medically necessary for all indications, including as an alternative method of performing NCSs.
Screening testing for polyneuropathy of diabetes or end stage renal disease (ESRD) in patients without clinical deficits is not indicated. Testing for the sole purpose of monitoring disease intensity or treatment efficacy in these two conditions is not indicated.
Psychophysical measurements (electrical, vibratory or thermal perceptions), even though they may involve delivery of a stimulus, are not covered.
Current Perception Threshold/Sensory Nerve Conduction Threshold Test (sNCT) is investigational and not covered. This procedure is different and distinct from assessment of nerve conduction velocity, amplitude, and latency. It is also different from short-latency somatosensory evoked potentials (SSEPs). Codes designated for eliciting nerve conduction velocity, latency, or amplitude and those designed for SSEPs are not to be used for sNCT. sNCT has a unique G code, G0255. Effective on October 1, 2002, CMS initially concluded that there was insufficient scientific or clinical evidence to consider the sNCT test and the device used in performing this test reasonable and necessary within the meaning of section 1862(a)(1)(A) of the law. Therefore, sNCT was not covered. Based on a reconsideration [in March, 2004] of current Medicare policy for sNCT, CMS concluded that there continues to be insufficient scientific or clinical evidence to consider the sNCT test and the device used in performing this test as reasonable and necessary within the meaning of section 1862(a)(1)(A) of the law (CMS Publication 100-3, Medicare National Coverage Issues Manual, Chapter 1, Section 160.23).
Examination using portable hand-held devices, which are incapable of real-time wave-form display and analysis, will be included in the evaluation & management (E/M) service. They will not be paid separately.
Beginning in 2012, three new CPT codes (95885, 95886 and 95887) have been created to report EMG studies performed the same day as nerve conduction testing. Each of these codes should be reported in conjunction with CPT Codes 95907-95913. Codes 95885 and 95886 can be reported together up to a combined total of four units per patient when all four extremities are tested. None of these codes should be reported with 95860-95864, 95870 or 95905.
It is expected that providers will use CPT code 95870 for sampling muscles other than the paraspinals associated with extremities, which have been tested. This code should not be billed when the paraspinal muscles corresponding to an extremity are tested and when the extremity EMG code 95860, 95861, 95863, 95864, 95885 or 95886 is also billed. If nerve conduction studies are performed on the same day, CPT Code 95887 is used instead.
The necessity and reasonableness of the following uses of needle EMG studies have not been established:
Maximum Number of Tests Necessary in 90% of Cases
Table 1, “Maximum Number of Studies,” summarizes the American Association of Neuromuscular & Electrodiagnostic Medicine’s (AANEM) recommendations regarding a reasonable maximum number of studies per diagnostic category necessary for a physician to arrive at a diagnosis in 90% of patients with that final diagnosis. Each number in the “Maximum Number of Studies Table” represents 1 study or unit. The table is designed as a tool to identify outlier trends and prevent abuse and overutilization. It is not an absolute maximum threshold and should not be used to automatically deny reimbursement over the maximum.
The maximum numbers, as shown in the table, are designed to apply to a diversity of practice styles, as well as practice types, including those at referral centers where more complex testing is frequently necessary. In simple and straightforward cases, fewer tests will be necessary. This is particularly true when results of the most critical tests are normal. In complex cases, the maximum numbers in the table will be insufficient for the physician to arrive at a complete diagnosis. In cases where there are borderline findings, additional tests may be required to determine if the findings are significant.
The appropriate number of studies to be performed should be left to the judgment of the physician performing the EDX evaluation; however, in the small number of cases which require testing in excess of the numbers listed in the table (the AANEM estimates 10% of cases), the physician should be able to provide supplementary documentation to justify the additional testing. Such documentation should explain what other differential diagnostic problems needed to be ruled out in that particular situation. Justification of the need to perform studies greater than that specified by the Maximum Number of Studies Table (Table 1) must be established at the time the EDX testing is performed and pertinent specific documentation included in the EDX testing report.
Multiple diagnoses might be established by EDX testing in up to 25% of patients. When multiple diagnoses are identified, the recommendations listed in Table 1 for a single diagnostic category may not apply. When multiple diagnoses are being considered, the appropriate number of studies is not arrived at by simply adding the number of studies identified for each diagnosis from Table 1. With only rare exception, the studies needed for different diagnoses “overlap” and a majority of the studies performed can be used in assessing multiple and different diagnoses. For example, one does not simply add the 10 studies allowed for polyneuropathy and the 7 studies allowed for lumbar radiculopathy to allow a total of 17 studies when these two diagnoses are being considered. In fact, all 7 of the studies utilized for the radiculopathy can be utilized in the assessment for polyneuropathy. Therefore, the 10 studies allowed for polyneuropathy are typically adequate to diagnose lumbar radiculopathy as well. Similarly, simultaneous diagnostic considerations such as cervical radiculopathy and carpal tunnel syndrome or lumbar radiculopathy and mononeuropathy would utilize the diagnosis with the higher number of allowed studies from Table 1.
It may be necessary to test selected muscles or nerves in a contralateral, at times asymptomatic, limb to better define the diagnosis. It is appropriate to bill for the additional testing and this is accounted for in the table below.
Limbs Studied by Needle Electromyography (95860-95864, 95867-95870, 95885-95887) Nerve Conduction Studies (Total nerve studied, 95907-95913) Neuromuscular
Number of Services (Tests) Number of Services (Tests) Number of Services (Tests) Carpal Tunnel (unilateral) 1 7 -- Carpal Tunnel (bilateral) 2 10 -- Radiculopathy 2 7 -- Mononeuropathy 1 8 -- Polyneuropathy/ Mononeuropathy Multiplex 3 10 -- Myopathy 2 4 2 Motor Neuronopathy (e.g., ALS) 4 6 2 Plexopathy 2 12 -- Neuromuscular Junction 2 2 3 Tarsal Tunnel Syndrome (unilateral) 1 8 -- Tarsal Tunnel Syndrome (bilateral) 2 11 -- Weakness, Fatigue, Cramps, or Twitching (focal) 2 7 2 Weakness, Fatigue, Cramps, or Twitching (general) 4 8 2 Pain, Numbness, or Tingling (unilateral) 1 9 -- Pain, Numbness, or Tingling (bilateral) 2 12 --
Carpal Tunnel Syndrome
For suspected carpal tunnel syndrome (CTS), bilateral median motor and sensory NCSs are often indicated. The studies in the contralateral asymptomatic limb serve as controls in cases where values are borderline and may establish the presence of bilateral CTS, which is a frequent finding. Two to 4 additional sensory or mixed NCSs can be compared to the median sensory NCSs to increase the diagnostic sensitivity of the testing. The additional sensory NCSs and an additional motor NCS (usually ulnar) are indicated to exclude a generalized polyneuropathy or multiple mononeuropathies.
If 2 sensitive sensory NCSs are performed at the beginning, additional sensory testing on the same limb is rarely needed. For suspected bilateral CTS, bilateral median motor and sensory NCSs are indicated. Up to 2 additional motor and 2 additional sensory NCSs are often indicated. The extent of the needle EMG examination depends on the results of the NCSs and the differential diagnosis considered in the individual patient.
Additional testing may be indicated in patients with a differential diagnosis which includes peripheral neuropathy, cervical radiculopathy, brachial plexopathy, or more proximal median neuropathy.
A minimal evaluation for radiculopathy includes 1 motor and 1 sensory NCS and a needle EMG examination of the involved limb. However, the EDX testing can include up to 3 motor NCSs (in cases of an abnormal motor NCS, the same nerve in the contralateral limb and another motor nerve in the ipsilateral limb can be studied) and 2 sensory NCSs. Bilateral studies are often necessary to exclude a central disc herniation with bilateral radiculopathies or spinal stenosis or to differentiate between radiculopathy and plexopathy, polyneuropathy, or mononeuropathy. H reflexes can provide useful complementary information that is helpful in the evaluation of suspected S-1 radiculopathy and can add to the certainty of EDX information supporting this diagnosis.
Radiculopathies cannot be diagnosed by NCS alone; needle EMG must be performed to confirm a radiculopathy. Therefore, these studies should be performed together by 1 physician supervising and/or performing all aspects of the study
In order to characterize the nature of the polyneuropathy (axonal or demyelinating, diffuse or multifocal) and in order to exclude polyradiculopathy, plexopathy, neuronopathy, or multiple mononeuropathies, it may be necessary to study 4 motor and 4 sensory nerves, consisting of 2 motor and 2 sensory NCSs in 1 leg, 1 motor and 1 sensory NCS in the opposite leg, and 1 motor and 1 sensory NCS in 1 arm. H-reflex studies and F-wave studies from 2 nerves may provide additional diagnostic information. At least 2 limbs should be studied by a needle EMG examination. Studies of related paraspinal muscles are indicated to exclude some conditions such as polyradiculopathy.
To diagnose a myopathy, a needle EMG examination of 2 limbs is indicated. To help exclude other disorders such as polyneuropathy or neuronopathy, 2 motor and 2 sensory NCSs are indicated. Two repetitive motor nerve stimulation studies may be performed to exclude a disorder of NMJ transmission.
In order to establish the diagnosis of motor neuronopathy (for example, amyotrophic lateral sclerosis [ALS or Lou Gehrig’s disease]) and to exclude other disorders in the differential diagnosis, such as multifocal motor neuropathy or polyneuropathy, up to 4 motor nerves and 2 sensory nerves may be studied.
Needle EMG of up to 4 extremities (or 3 limbs and facial or tongue muscles) is often necessary to document widespread denervation and to exclude a myopathy. One repetitive motor nerve stimulation study may be indicated to exclude a disorder affecting NMJ transmission.
To characterize a brachial plexopathy and to differentiate it from cervical radiculopathy and mononeuropathies it may be necessary to perform additional sensory studies (e.g., medial and lateral antebrachial cutaneous nerves) for a total of up to 6 sensory studies. It may also be necessary to perform up to 4 motor studies.
To characterize a lumbosacral plexopathy and to differentiate it from lumbosacral radiculopathy, mononeuropathies and polyneuropathy, it may be necessary to perform up to 4 sensory studies, up to 4 motor studies and up to 2 H-reflex studies.
For both brachial and lumbosacral plexopathies, up to 2 additional studies (sensory and/or motor) may be performed in the contralateral (at times asymptomatic) limb to better definite the diagnosis.
To demonstrate and characterize abnormal NMJ transmission, repetitive nerve stimulation studies should be performed in up to 3 nerves and SFEMG in up to 2 muscles. If any of these are abnormal, up to 2 motor and 2 sensory NCSs may be performed to exclude neuropathies that can be associated with abnormal NMJ transmission. At least 1 motor and 1 sensory NCS should be performed in a clinically involved limb, preferably in the distribution of a nerve studied with repetitive stimulation or SFEMG. At least 1 distal and 1 proximal muscle should be studied by a needle EMG examination to exclude a neuropathy or myopathy that can be associated with abnormal repetitive stimulation studies or SFEMG. At least 1 of the muscles should be clinically involved and both muscles should be in clinically involved limbs.
Timing of Testing After an Injury
In combination, NCSs and a needle EMG examination may be most helpful when performed several weeks after the injury has occurred. However, NCSs are often useful acutely after nerve injury, for example, if there is concern that a nerve has been severed. In fact, if studies are delayed, the opportunity to precisely identify the region of injury or to intervene may be lost. In some cases, even needle EMG testing performed immediately after a nerve injury may demonstrate abnormal motor unit action potential (MUAP) recruitment and/or provide information that can be helpful to document preexisting conditions, date the injury, or serve as a baseline for comparison with later studies.
Because of the variability of different nerve injuries, a standard rule on the timing of EDX testing cannot easily be established, and the AANEM does not have specific recommendations in this regard. In all instances, the AANEM encourages dialogue between physicians and payers, and encourages the appropriate use of the physician’s clinical judgment in determining when studies are most appropriately performed and what studies should be conducted.
Frequency of Electrodiagnostic Testing in a Given Patient
There are many clinical situations where good medical management requires repeat testing, such as in the following examples:
Repeat EDX evaluation is, therefore, sometimes necessary and, when justifiable, should be reimbursed. Reasonable limits can be set concerning the frequency of repeat EDX testing per year in a given patient by a given EDX evaluation for a given diagnosis. The following numbers of tests per 12-month period per diagnosis per physician are acceptable:
These limits should not apply if the patient requires evaluation by more than 1 EDX physician (i.e., a second opinion or an expert opinion at a tertiary care center) in a given year or if the patient requires evaluation for a second diagnosis in a given year. Additional studies then may be required or appropriate above these guidelines. In such situations, the reason for the repeat study should be included in the body of the report or in the patient's chart. Comparison with the previous test results should be documented. This additional documentation from the physician regarding the necessity for the additional repeat testing would be appropriate. Repeat EDX testing should not be necessary in a 12-month period in 80% of all cases.
- American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) Position Statement. Recommended Policy for Electrodiagnostic Medicine.
- AANEM Position Statement. Proper Performance and Interpretation of Electrodiagnostic Studies.
- AANEM Position Statement. Who is Qualified to Practice Electrodiagnostic Medicine.
- AANEM Education Report. Reporting the Results of Needle EMG and Nerve Conduction Studies.
- AANEM Evidence-Based Review. Use of Surface Electromyography in the Diagnosis and Study of Neuromuscular Disorders. Muscle & Nerve. 38: 1219-24, 2008.
- Brown, Elizabeth. An Evidence Based Technology Assessment of the NC-stat® Device. March 19, 2007
- Hayes brief. Nc-stat System (NeuroMetrix Inc.) for Noninvasive Nerve Conduction Testing of Upper Extremity Neuropathy. February 27, 2007.
- Lefevre, Frank. An evidence review of the diagnostic accuracy of automated nerve conductions studies compared to traditional nerve conduction studies. May 22, 2008.
- Morse, Josh. NC-stat® System, NeuroMetrix® Inc. (Nerve Conduction Testing System) Technology Assessment. June 8, 2006. Accessed 2010 http://www.lni.wa.gov/ClaimsIns/Providers/Treatment/CovMedDev/SpecCovDec/NCstat.asp)
Creation of New Guidelines, Consensus Statements, or Position PapersAANEM members are encouraged to submit ideas for papers that can improve the understanding of the field. The AANEM will review nominated topics on the basis of the following criteria:
- Members’ needs
- Prevalence of condition
- Health impact of condition for the individual and others
- Socioeconomic impact
- Extent of practice variation
- Quality of available evidence
- External constraints on practice
- Urgency for evaluation of new practice technology