Neurology & Pain Management Coding Alert

Question: How should I code for recording of M-waves? Are these similar to F-waves?

Oregon Subscriber

Answer: The M-wave is the compound motor action potential (CMAP) that the physician records by stimulating a motor nerve. The neurologist obtains this reading as an integral part of a motor nerve conduction study (95900, Nerve conduction, amplitude and latency/velocity study, each nerve; motor, without F-wave study). You should report a single unit of 95900 for each separate motor nerve the physician tests.

The F-wave is a late response that occurs after an M-wave response. The neurologist uses F-waves to assess the proximal segments of the motor nerve function for the evaluation of plexopathy, radiculopathy, polyradiculoneu-ropathy and other proximal or multifocal disorders. You should report an F-wave motor nerve conduction study using 95903 (... motor, with F-wave study). Again, you may bill a single unit for each separate motor nerve the physician tests.

You are "unbundling" if you bill 95900 and 95903 when the physician performs F-wave and motor conduction studies on the same nerve. In such cases, you should report only 95903.

If the neurologist performs motor conduction studies on some nerves and motor nerve studies with F-waves on different nerves, however, you may bill 95900 and 95903 at the same time. To support your claim, the American Academy of Neurology suggests submitting documentation specifying the number of nerves tested. And CMS recommends appending modifier -59 (Distinct procedural service) to the second and subsequent codes to indicate a different anatomic area and avoid bundling.