Neurology & Pain Management Coding Alert

You needn’t pay attention to the number of doses or time spent for the testing.

Testing for muscle strength in myasthenia gravis may test your patience, but a single code might be all you need.

Scenario: Your neurologist may conduct an Edrophonium test when other diagnostic testing has been inconclusive in detecting if the patient has myasthenia gravis. "Your neurologist may also refer to this as a Tensilon or cholinesterase inhibitor challenge test," says Marvel Hammer, RN, CPC, CCS-P, PCS, ACS-PM, CHCO, owner of MJH Consulting in Denver, CO. "The diagnostic test can also be used to differentiate myasthenia gravis from cholinergic crisis and Lambert-Eaton myasthenic syndrome."

Testing components: The testing consists of intravenous administration of the drug with monitoring for any improvement in muscle strength. Typically, an initial test dose of 2 mg is given to watch for the possibility of an exaggerated response, such as heart rate abnormalities like bradycardia. The patient may be asked to perform some repetitive muscular movements such as crossing and uncrossing of legs or getting up from a sitting position in a chair. While watching for any sudden, although temporary, improvement in the patient’s muscle strength, the neurologist will often inject IV additional edrophonium up to 10 mg if the patient has no response to the initial injection. In a positive test, most myasthenic muscles respond in 30 to 45 seconds after injection with the improvement in strength lasting up to five minutes.

If this example looks familiar, knowing the answers to three important questions can ensure you correctly report cholinesterase inhibitor testing.

1. Can You Report Various Doses Administered?

Your physician may use a series of doses when conducting the edrophonium test. Because testing with additional doses is not beyond the usual service, you cannot report multiple units of 95857 (Cholinesterase inhibitor challenge test for myasthenia gravis). You will only report one single unit of 95857, regardless of the number of doses your physician injects for the testing.

2. Can You Report Additional Time Spent on the Test?

Your clinician may only need one dose for testing some patients, but administers two or more doses for other patients.

Providers usually wait about 30 minutes between consecutive doses. During this period, your clinician monitors the patient for side effects such as lacrimation, nausea, and vomiting. The inherent waiting period means your physician spends more time on testing when the patient needs multiple doses.

Once again, however, the extended time is not beyond the usual service. Do not report prolonged services codes 99354 (Prolonged service in the office or other outpatient setting requiring direct patient contact beyond the usual service; first hour [List separately in addition to code for office or other outpatient Evaluation and Management service]) -- 99357 (Prolonged service in the inpatient or observation setting, requiring unit/floor time beyond the usual service; each additional 30 minutes [List separately in addition to code for prolonged service]) with 95857.

Note: The only time that you may report a modifier 22 (Unusual procedural service) is when a complication arises. Verify that you have clear documentation from your clinician supporting that the service was performed beyond protocol of the test.

Also: Include J0461 (Injection, atropine sulfate, 0.01 mg) if the provider administers the medication to alleviate side effects. Check with your payer for coverage instructions for atropine. However, there isn’t a specific code in the HCPCS Table of Drugs for edrophonium used in the testing. You may report code J3490 (Unclassified drugs) for 10 mg/mL of edrophonium chloride.

3. How Do You Report Additional Tests for Myasthenia?

Sometimes a physician obtains single fiber electromyogram (EMG) to diagnose myasthenia gravis or to assess the improvement in muscle activity during the cholinesterase inhibitor challenge test. If so, you submit the code 95872 (Needle electromyography using single fiber electrode, with quantitative measurement of jitter, blocking and/or fiber density, any/all sites of each muscle studied). Another test that your neurologist may do is the repetitive nerve stimulation. You report code 95937 (Neuromuscular junction testing [repetitive stimulation, paired stimuli], each nerve, any 1 method) for this.