Look to Combo Codes on Some Evoked Potentials
Question: A 58-year-old presents with a year of progressive weakness and stiffness in both legs and their right arm, with spasticity and hyperreflexia upon exam. The neurologist evaluates the descending motor pathway with a central motor evoked potential (EP) study, using transcranial stimulation to record compound muscle action potentials from upper and lower limb muscles and calculate central motor conduction times. How should I report this encounter? Illinois Subscriber Answer: Since the neurologist tested both upper and lower limbs, the correct code is 95939 (Central motor evoked potential study (transcranial motor stimulation); in upper and lower limbs). As this combination code exists, CPT® forbids you from reporting 95928 (Central motor evoked potential study (transcranial motor stimulation); upper limbs) and 95929 (… lower limbs) together for this encounter. The documented findings prove medical necessity for the EP. Append M62.81 (Muscle weakness, (generalized)) and R26.2 (Difficulty in walking, not elsewhere classified) to 95939 to represent the patient’s symptoms; substitute them with a more specific diagnosis if/when one is reached. Facility factor: If the neurologist obtained the EP at the office with their practice’s equipment, your coding is complete. If they used someone else’s equipment — such as a hospital’s — and only provided the interpretation and report, append modifier 26 (Professional component) to 95939. Jennifer McNamara, CPC, CVBA, CRC, CPMA, CDEO,
CEMA, COSC, CGSC, COPC, CPC-I, Contributing Writer
