Nerve conduction studies (NCS) are used to measure action potentials resulting from peripheral nerve stimulation recordable over the nerve or from an innervated muscle.  Nerve conduction velocity measurement, one aspect of a nerve conduction study, is measured between two sites of stimulation , or between a stimulus and a recording site.  Nerve conduction studies are of two broad types:  Sensory and Motor.  Either surface or needle electrodes can be used to stimulate the nerve or record the response.  

 

Electromyography (EMG) is the study and recording of intrinsic electrical properties of skeletal muscles.  This is carried out with a needle electrode of which there are two types:

This testing is invasive in that it requires needle insertion and adjustment at multiple sites, and at anatomically critical areas.  EMG testing relies on both the auditory and visual feedback to the electromyographer.  

 

The intensity and extent of testing with EMG and NCS are matters of clinical judgment developed after the initial pre-test evaluation and later modified during the testing procedure.  Decisions to continue, modify or conclude a test rely on a knowledge base of anatomy, physiology and neuromuscular diseases.  There is a requirement for ongoing real-time clinical evaluation, especially during the EMG examination.

 

The person performing electrodiagnostics should be appropriately trained and qualified.  They must have detailed knowledge of neuromuscular diseases and an awareness of the influence of age, temperature and body height on the results.

 

The patient's medical records must clearly document the medical necessity for the test.  Referral data containing pertinent clinical information must be available in instances where the need for a test may be questioned.  The NCS-EMG performing provider, in addition to the referring provider, is responsible for determination of the appropriateness of a study.

 

Frequency of testing is a difficult question to address.  Clinical justification, rather than an algorithm, should be dominant in these instances.  This requires clear, responsible and evidence-based documentation for any repeat study.

 

 

 

Nerve Conduction Studies:

The division into axonal and demyelinating neuropathies provides a practical means of correlating electrical abnormalities with major pathophysiologic changes in the nerve.  Electrical studies can be of help in localization of an abnormality, and in distinguishing  one variety of neuropathy from another.  Such distinction has diagnostic value.  Classification of nerve injuries into neuropraxia and axonotmesis can be made on the basis of electrodiagnostic studies and this has a bearing on prognosis and treatment.

 

The Nerve Conduction Study codes refer to testing done using standard electrodiagnostic equipment.  This equipment must be capable of recording amplitude, duration and response configuration (motor NCV) and latency and sensory nerve action potential amplitudes (sensory NCV).  Examinations using portable handheld devices such as the Neural-Scan are included in a visit and should not be billed separately.  Noninvasive electrodiagnostic testing with automated and/or hand-held devices to stimulate and measure neuromuscular signals in diagnosing and evaluating systemic and entrapment neuropathies should be billed with S3905.  Examples of these devices include, but are not limited to, NC-stat, XLTek Neuropath, Neurometer  and Brevio.  

 

The number of nerves tested should be the minimum needed to establish the diagnosis.

 

The following is a list of the most common indications for NCS and the number of tests considered medically necessary in most cases (the first number represents Motor NCV and the second number represents Sensory NCV):

 

One unit of service includes all studies done on a single nerve including latency, velocity, amplitude, and response configuration with antidromic and/or orthodromic stimulation and F-wave (for those studies that include F-wave).

 

Repeat NCV testing within twelve months will be denied, unless accompanied by an explanation of medical necessity that provides clinical rationale that justifies the need for additional testing in this time period.   Undocumented repeat services will be considered not medically necessary.

 

Nerve Conduction Studies performed by Occupational/Physical Therapists meet primary coverage criteria for effectiveness and are covered if rendered by a therapist who has had special training in performing this type of testing.  Reimbursement to the therapist is limited to the technical component of the procedure only.  In order for the technical component of the test to be reimbursed to the therapist the NCS must be:

Services not meeting these conditions will be considered not medically necessary.

 

Screening testing for polyneuropathy (not mononeuropathies) of diabetes or end-stage-renal-disease (ESRD) is NOT covered.  Testing for the sole purpose of monitoring disease intensity or treatment efficacy in these two conditions is also not covered.  Screening tests are an exclusion in the member certificate of coverage.

 

The list of nerves included in each CPT procedure code, as listed in the April 2003 CPT Assistant are:

 

Codes 95900 and 95903 involve the following nerves:

 

Code 95904 involves the following nerves:

 

Electromyography:

Neurogenic disorders are distinguishable from myopathic disorders by a carefully performed EMG.  Classification of nerve trauma into axonal vs. demyelinating categories, with corresponding differences in prognoses, are possible with EMG.  A list of common disorders where an EMG, in tandem with properly conducted NCS, will be helpful includes:

 

The number of limbs tested should be the minimum to establish the diagnosis.

 

Electromyography of the extremities or the cranial nerves performed by Occupational/Physical therapists meets primary coverage criteria for effectiveness and is covered.  Reimbursement to the therapist is limited to the technical component of the procedure.  In order for the technical component for the EMG to be reimbursed to the therapist the test must be:

Services not meeting these conditions will be considered not medically necessary.

 

For codes 95860-95864, only one unit of service should be billed.  This covers all muscles tested including the related paraspinal muscles and recording of the motor unit recruitment , amplitude and configurations at rest and with muscle contraction.  To bill these codes, extremity muscles innervated by three nerves or four spinal levels must be evaluated; a minimum of five muscles must have been studied.  Services not meeting these conditions will be considered not medically necessary.

 

CPT 95867-95869 are used to bill a limited needle EMG of specific muscles  Theses codes will be denied if billed with more than one unit of service.  Examinations confined to distal muscles only, such as intrinsic foot or hand muscles, will be reimbursed as 95869, not 95860-95864.  Additional services will be considered not medically necessary.

 

CPT 95870 can be billed at one unit per extremity when fewer than 5 muscles are examined.  This code can be used for examining muscles on the thorax or abdomen (unilateral or bilateral).  One unit may be billed for studying cervical or lumbar paraspinal muscles (unilateral or bilateral), regardless of the number of levels tested.  This code should not be billed when the paraspinal muscles corresponding to an extremity are tested and when the extremity codes 95860-95864 are also billed.  Services not meeting these conditions will be considered not medically necessary.

 

Peer reviewed medical literature has not established the effectiveness of EMG by other than needle technique.   

 

EMG by other than needle technique for diagnostic purposes is not covered based on benefit certificate primary coverage criteria that there be scientific evidence of effectiveness.

 

For contracts without primary coverage criteria, EMG by other than needle technique for diagnostic purposes is considered investigational.  Investigational services are an exclusion in the member certificate of coverage.

 

CPT 51784 will be allowed for children less than 14 yrs of age.