Neurology & Pain Management Coding Alert

Question: What diagnosis codes are appropriate to bill for nerve conductions in a patient who has a history of chronic inflammatory demyelinating polyneuropathy (CIDP), but has new leg weakness? The studies were done to rule out CIDP and were negative.

Georgia Subscriber

Answer: If CIDP is not the cause of the new leg weakness, you should not use it as a diagnosis. Rather, many carriers will accept signs and symptoms code 728.9 (Unspecified disorder of muscle: muscle weakness) in this instance. Cahaba GBA(the Medicare carrier for Georgia), for example, states the following in its local medical review policy (LMRP) on nerve conduction studies (NCS) and electromyography (EMG):

The Carrier is cognizant of the fact that patients are not always referred with a definite diagnosis in mind. Often, pain, paresthesia or weakness in an extremity is the reason for an NCV or EMG. These common symptoms result not only from axonal and myelin dysfunction but also from systemic, non-neurological illnesses. EMG and NCV may help in making this distinction. Therefore, symptom-based diagnoses such as pain in limb (729.5), weakness (728.9), disturbance in skin sensation (782.0) or "paresthesia" are acceptable, provided the clinical assessment unequivocally supports the need for a study.

Some other states that also permit you to use symptom-based diagnosis codes for reimbursement include New Mexico, Oklahoma, Pennsylvania, Tennessee, and Virginia. Be sure to check the LMRP of your state Medicare carrier for specific coding guidelines.