Neurology & Pain Management Coding Alert

Question: Our neurologist has been treating a patient with pain in his fingers that traveled up his arm. The patient also has a weakened grip. The physician suspected that the patient had carpal tunnel syndrome (CTS), so he ran a motor nerve conduction study without F-wave, as well as a single-extremity complete-needle electromyography study. This confirmed the CTS diagnosis, and the neurologist performed a steroid injection into the carpal tunnel as treatment. When I code the primary diagnosis, should this be the original pain and weakened grip, or the CTS?

Oregon Subscriber

Answer: Because your neurologist has confirmed the diagnosis as CTS, you-re right to use 354.0 (Carpal tunnel syndrome) for the primary diagnosis for the electrodiagnostic studies performed.

Word of warning: Don't jump the gun with 354.0 just because your physician suspects that a patient has CTS. If you use this code as medical necessity for payer authorization of the diagnostic studies, you could be reporting a diagnosis for a condition that the patient may not have.

Until testing confirms your neurologist's CTS diagnosis, you should depend on symptoms to justify any services the physician provides. This move will also keep you in line with ICD-9 official guidelines, which instruct you to report signs and symptoms when the provider has not established a related definitive diagnosis.

How to code the procedures: Code the electrodiagnostic testing your neurologist conducted using 95900 (Nerve conduction, amplitude and latency/velocity study, each nerve; motor, without F-wave study) for the nerve conduction studies and 95860 (Needle electromyography; one extremity with or without related paraspinal areas) for the electromyography.

Code for the steroid injection your neurologist performed as an anti-inflammatory using 20526 (Injection, therapeutic [e.g., local anesthetic, cortico-steroid], carpal tunnel).

Bonus dx info: Regarding the original diagnosis, the patient's digital pain that moved up his arm and his weakened grip are typical symptoms and signs that indicate carpal tunnel syndrome. If your neurologist hadn't confirmed a diagnosis of CTS -- if the diagnostic studies were normal or inconclusive, for example -- you would have coded for these conditions using 729.5 (Pain in limb) and 728.87 (Muscle weakness [generalized]).

Good advice: You should rely only on the signs and symptoms to establish medical necessity for the tests the neurologist conducts, as well as any E/M service he provides. Always make sure the physician's documentation is strong enough to support the claim, regardless of the outcome of diagnostic testing.