Eli's Rehab Report

Before you select an NCS code, you must determine which nerve fiber types the physiatrist tested.

All nerves contain motor fibers, sensory fibers or a mixture of the two, says Neil Busis, MD, director of the neurodiagnostic laboratory at the University of Pittsburgh Medical Center at Shadyside.

Codes 95900 and 95903 describe motor fiber testing (the former without F-wave study, the latter with F-wave study), while code 95904 describes sensory or mixed fiber testing. During NCS, the physiatrist places a stimulating electrode at one location along the nerve and a recording electrode at another location along the same nerve. The stimulating electrode delivers a low-level electrical charge, while the recording electrode measures the resulting nerve function.

Coding example: A physiatrist places stimulating electrodes on the radial motor nerve with recording electrodes at the extensor indicis proprius. He conducts the test without F-waves. Because this nerve contains motor fibers only, you should report one unit of 95900, Busis says. If the physiatrist had included an F-wave study, you would report 95903 instead.

If the physiatrist tested a sensory nerve, such as the median sensory nerve, 95904 would be appropriate. If he tested a single nerve containing both sensory and motor fibers (such as the median mixed nerve in the palm, which connects to the lumbrical muscles), you would report 95904.

2. Count the Billable Units

Important: Report multiple units of NCS when appropriate, because failing to do so will seriously compromise your reimbursement.

Don't miss: The number of billable units does not necessarily correspond to the number of extremities the physiatrist tests, says Tiffany Schmidt, JD, policy director for the American Association of Electrodiagnostic Medicine (AAEM). Rather, the number of billable units depends on the number of nerves that the physician tests. "We are encouraging people to use the list of nerves published in the April 2003 CPT Assistant," Schmidt says.

Note: You can view the nerve list on the AAEM Web site at http://www.aaem.net/aaem/practiceissues/RecPolicy/ListofNerves.cfm.

Coding example 1: The physiatrist studies the median motor nerve to the abductor pollicis brevis and then tests the median motor nerve to the first lumbrical. You should report two units of 95900 because you tested two separate nerves.

Coding example 2: The physiatrist stimulates the median motor nerve to the first lumbrical (without F-waves) and then stimulates the anterior interosseous branch of the median motor nerve while recording at the pronator quadratus (with F-waves).

In this case, you should report one unit each of 95900 and 95903 because the physiatrist studied two different nerves -- one with F-waves and one without. Had the physiatrist stimulated the median motor nerve to the first lumbrical, first without F-waves and then with F-waves, however, you would report 95903 only (the study without F-waves is included in the study with F-waves).

Watch out: Some insurers reject 95900 and 95903 if you perform them during the same session, arguing that 95900 is a component of 95903. The National Correct Coding Initiative (NCCI) does bundle these codes, but the bundle applies only if you report both codes for the same location. If the physiatrist conducts one of each type of study on separate nerves, you may report two separate studies, Busis says. Append modifier -59 (Distinct procedural service) to 95900 and send the insurer a procedure report or letter explaining that the physician tested two different nerves.
 
3. Keep Use/Frequency Limits in Mind

If you report multiple NCS units or test the same patient on different dates, be aware of payers' use and frequency guidelines. Generally, insurers abide by the AAEM's "Recommended Policy for Electrodiagnosic Testing," which includes a chart listing the "maximum number of tests necessary in 90 percent of cases" for a variety of diagnostic categories and electrodiagnostic tests (such as NCS, EMG, etc.).

Take note: The AAEM's chart lists the maximum recommended number of NCS units for radiculopathy as three motor units (either 95900 or 95903) and two sensory units (95904), for example. Although payers may allow you to exceed the AAEM's recommend maximums in some cases, your documentation must clearly support the necessity. "Without a thorough explanation, the insurer's going to reject the claim," Schmidt says.

And major insurers such as Aetna set frequency guidelines, specifying, for instance, 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, polyneuropathy, myopathy and neuromuscular junction disorder, but stating the payer may reject more than two claims per year as excessive.

4. Provide the Documentation to Back it Up

Complete documentation is crucial to prompt and appropriate NCS payment, Schmidt says. The AAEM recommends documenting the nerves the physician evaluated, the distance between the stimulation and recording sites, and the conduction velocity, latency values, and amplitude for each study.