Neurology & Pain Management Coding Alert

1. Motor NCS (95900 and 95903) involves stimulation at various points along a motor nerve containing motor fibers only. The response is recorded from a muscle innervated by those fibers.

Code 95903 is distinguished from 95900 by the recording of F-waves. The set up for an F-wave study (95903) is similar to that of a regular nerve conduction study (95900), but testing is conducted separately using different machine settings and separate stimulation to obtain more responses (generally, at least 10). Two coding examples illustrate the difference between these codes:

2. Sensory NCS (95904) involves stimulation of sensoryfibers only, with recording on a different site along the same nerve, or stimulation of a nerve containing motor and sensory fibers while recording over apurely sensory branch of the same nerve.

An example is stimulation at medium sensory nerve, recorded at the first and second digits. Code one unit of 95904.

3. Mixed NCS (95904) involves the stimulation of a nerve containing both motor and sensory fibers (a mixed nerve) and recording from a different location (also containing both motor and sensory nerve fibers) along the same nerve.

CPT 2002 eliminated the term "or mixed" from the descriptor of 95904 to avoid the mistaken conclusion among some insurers and coders that 95904 was used to bundle motor and sensory studies (i.e., instead of reimbursing for one motor study [95900/95903] and one sensory study [95904], the insurer paid for a single "mixed" study [95904]). A true mixed NCS, however, is separate and distinct from either sensory or motor studies and should be reimbursed accordingly. An example shows how to code for a mixed nerve:

Determining and billing for the proper number of NCS depends on the location of the electrodes, not necessarily the number of nerves tested. If the recording or stimulating electrode remains stationary during the study, only one unit of any NCS code may be reported. If the recording and stimulating electrodes are moved even to a different location on the same nerve multiple units may be claimed. By extension, if multiple nerves are tested, multiple units may be reported.

If you provide NCS to diagnose carpal tunnel syndrome (CTS), the median mixed nerve, median sensory nerve and median motor nerve may all be tested. In this case, report two units of 95904 (once for sensory NCS and once for mixed NCS) and 95900.

Note: All NCS codes (95900, 95903 and 95904) are modifier -51 (Multiple procedures) exempt, Tiffany Eggers, JD, MPA, policy director and legislative counsel for the American Association of Electrodiagnostic Medicine (AAEM) says. Therefore, when reporting testing on multiple nerves, do not append modifier -51 to the second and subsequent tests. If an insurer rejects a claim involving multiple nerve studies, CMS recommends attaching modifier -59 (Distinct procedural service) to the second and subsequent NCS codes.

Some payers reject 95900 and 95903 when they are reported together, says Eggers, arguing that the first code is a component of the second. This is true but only if both codes are reported for the same nerve. If one of each type of study is conducted on separate nerves, two separate studies may be reported. Some sample scenarios follow:

A. Stimulation at the median motor nerve, recorded at the abductor pollicis brevis. Stimulation at the same location, recorded at the first lumbrical, with F-waves. Report one unit of 95903. In this case, only the recording electrode is moved, therefore only one unit is billable. The study without F-waves is bundled to the study with F-waves.

B. Stimulation at the median motor nerve, recorded at the adductor pollicis brevis. Stimulation at the anterior interosseous branch of median motor nerve, recorded at the pronator quadratus, with F-waves. Bill 95900, 95903. Both the stimulating and recording electrodes are moved. Therefore, two separate studies can be billed for the same nerve.

C. The conditions are the same in example B, but without F-waves on the second study. Report two units of 95900. Again, the stimulating and recording electrodes are moved. Two studies can be billed for separate branches on the same nerve.

D. Stimulation at the median motor nerve, recorded at the adductor pollicis brevis. Stimulation at the radial motor nerve recorded at the extensor digitorum communis, with F-waves. Report 95900, 95903. The stimulating and recording electrodes are moved. Because the studies with and without F-waves occurred on different nerves, both are billable.

Note: A second method to determine the number of billable NCS is to refer to a list of studies that qualify as separate procedures. The AMA has published a preliminary list of such studies on pages 374-375 of Principles of CPT Coding, Second Edition. A final list is due to be announced shortly. Stay tuned to Neurology Coding Alert for complete coverage.

Documentation is crucial for NCS claims, warns Dianna Hofbeck, RN, CCM, ACFE, president of North Shore Medicine Inc., a national billing service in Abescon, N.J. The AAEM recommends documenting the nerves evaluated, the distance between the stimulation and recording sites, and the conduction velocity, latency values and amplitude for each study. At minimum, Eggers suggests that documentation should note the number of nerves tested and indicate if additional branches of the same nerve were tested separately. Without such explanation, insurers are likely to reject multiple units of the same code (such as in Example B, above) as a duplication of services.

Including a hard copy of the NCS as part of the medical chart does not usually add useful information to the report. Nevertheless, Hofbeck recommends filing a manual, hard copy of all NCS claims with documentation attached.

Individual insurers will accept different diagnoses to justify billing for NCS. Aetna U.S. Healthcare, for instance, allows over a dozen different diagnoses, ranging from CTS (354.0) to myopathy (359.x) to spinal cord injury (952.9).

In addition, insurers will often provide specific coverage limitations on NCS. For example, Aetna will not reimburse for F-wave studies for a diagnosis of CTS because "it is medically unnecessary to perform an F-wave study for this condition." The policy further specifies that use of 95900-95904 "at a frequency of two times per year would be considered appropriate for most conditions," including unilateral or bilateral carpal tunnel syndrome, radiculopathy, mononeuropathy, polyneu-ropathy, myopathy and neuromuscular junction disorders. Aetna also provides a list of the maximum number of NCS it will reimburse for a given diagnostic category. Again, neurology practices should contact their carriers for a list of accepted diagnoses for NCS and coverage limitations.

Note: The AAEM has adopted a recommended national policy for electrodiagnostic testing (which has been endorsed by the American Academy of Neurology) that provides valuable information on NCS, such as the maximum number of studies for each diagnostic category (on which Aetna and other insurers often base coverage decisions). View the policy at http://www.aaem.net/aaem/position_statements/recommended_policy_3.cfm . For more on gathering information on insurer policies using the internet, see the box below.