Neurosurgery Coding Alert

Providers use test to check for MS, other neuro conditions.

When your provider performs an evoked potential (EP) study, they could be checking the patient for any number of conditions. They could also employ several different tests, meaning you’ll need to know the differences between each type of EP study.

We asked Amy Pritchett, CCS, CPC-I, CPMA, CDEO, CASCC, CANPC, CRC, CDEC, CMPM, C-AHI, senior consultant at Pinnacle Enterprise Risk Consulting Services LLC in Centennial, Colorado, for the lowdown on two types of EP studies: short-latency and central motor. (There are other types of EP studies as well, but we focused on these two common EP studies for this article.)

Here’s what she had to say.

Know What EP Studies Test for

According to Cleveland Clinic, “evoked potentials test and record how quickly and completely the nerve signals reach the brain. These tests can be helpful in diagnosing such conditions as multiple sclerosis and other neurological disorders.”

If you see a test that is testing how long it takes for the brain to respond to sensory stimulation, it could be an EP study.

Use 95925-95927 for Short-Latency EPs

When a patient reports to the provider for a short-latency EP study, the provider will perform a test described by one of the following CPT^® codes:

o 95925 (Short-latency somatosensory evoked potential study, stimulation of any/all peripheral nerves or skin sites, recording from the central nervous system; in upper limbs) During 95925 service, “the physician performs a potential study by stimulating the peripheral nerves or skin sites in the upper limbs. The provider will record the resulting study from the central nervous system,” explains Pritchett.
o 95926 (… in lower limbs) During 95926 service, the provider performs “stimulation of any and all peripheral nerves or skin sites with recording from the central nervous system in the lower limbs,” according to Pritchett.
o 95938 (… in upper and lower limbs) During 95938 service, the provider performs the actions described by 95925 and 95926, eliminating the need to submit two codes.
o 95927 (… in the trunk or head) During 95927 service, the provider performs “stimulation of any and all nerves or skin sites, recording from the central nervous system in the trunk or head,” Pritchett explains.

Out of order: You’ll notice that 95938 is out of numerical order. This isn’t a typo; this code was resequenced, or moved from its original spot in the CPT^® code book and into this group. CPT^® moved the code because it made sense to have 95938 with this code set — despite it being out of numerical order. Whenever you see a hashtag (#) beside a CPT^® code, it means that the code was resequenced.

Short-Latency EPs Could Lead to These Diagnoses

When a patient undergoes a short-latency EP study, the provider is checking to confirm (or deny) certain conditions. Here are some of the diagnoses you might see accompanying an EP study:

• Myasthenia gravis: G70.00 (Myasthenia gravis without (acute) exacerbation)
• Spinal cord or head injuries: Various ICD-10 codes for injuries to both areas
• Cervical spondylotic myeloradiculopathy: M47.- (Spondylosis)
• Thoracic outlet syndrome: G54.0 (Brachial plexus disorders)
• Metabolic disorders (e.g., lead toxicity and/or B12 vitamin deficiency): T56. 0X1A (Toxic effect of lead and its compounds, accidental (unintentional), initial encounter), D51.9 (Vitamin B12 deficiency anemia, unspecified)
• ALS: G12.21 (Amyotrophic lateral sclerosis)

Note: This is not a complete list of ICD-10 codes that prove medical necessity for 95925-95927. It is merely a list of conditions that your provider could discover during a short-latency EP. Always code to the notes, and check with your payer if you have questions regarding short-latency EPs and ICD-10 codes.

Use 95928-95939 for Central Motor EP Study

If the provider performs an EP study that focuses on stimulating the central motor functions, you’ll report a central motor EP. Report central motor EPs with the following codes, depending on encounter specifics:

• 95928 (Central motor evoked potential study (transcranial motor stimulation); upper limbs)

During a 95928 EP, “the provider performs a central motor evoked potential study by transcranially stimulating the motor cortex by applying a very mild electric current to the scalp. In this procedure, the ultimate goal is to evaluate the motor pathways that supply the upper limb muscles,” says Pritchett.

• 95929 (… lower limbs)

During 95929 service, “the provider performs a central motor evoked potential study by transcranially stimulating the motor cortex by applying a mild electric current on the scalp. In this procedure, the ultimate goal is to evaluate the motor pathways supplying the lower limb muscles,” according to Pritchett.

• 95939 (… in upper and lower limbs)

During 95939 service, “the provider performs a central motor evoked potential study in both the upper and lower limbs for a diagnosis of multiple sclerosis and can also be utilized as an indicator for stroke motor recovery,” says Pritchett.

Central Motor EPs Could Lead to These Diagnoses

When a patient undergoes a central motor EP study, the provider is checking to confirm (or deny) certain conditions. Here are some of the diagnoses you might see accompanying an EP study:

• Temporal bone lesion: D16.4 (Benign neoplasm of bones of skull and face)
• Malignant neoplasm of spinal meninges: C70.1 (Malignant neoplasm of spinal meninges)
• Compression of brain: G93.- (Other disorders of brain)
• Trigeminal neuralgia: G50.0 (Trigeminal neuralgia)
• Dissection of abdominal aorta: I71.4- (Abdominal aortic aneurysm, without rupture)

Note: As with the previous ICD-10 list, this is not a complete accounting of ICD-10 codes that prove medical necessity for 95928-95939. It is merely a list of conditions that your provider could discover during a central motor EP. Always code to the notes, and check with your payer if you have questions regarding central motor EPs and ICD-10 codes.

Unilateral Calls for Modifier 52

You’ll notice that most of the EP codes describe bilateral procedures. If your provider performs a unilateral EP study, remember to append modifier 52 (Reduced services) and modifiers LT/RT (Left side/Right side) to the EP code to indicate reduced services and laterality, respectively.