CPT code 95937 – Neuromuscular junction testing

Key takeaways

CPT 95937 reports neuromuscular junction testing, such as repetitive stimulation or paired stimuli, and is billed once for each nerve tested.

Testing one nerve at several stimulation rates is still one unit, and Medicare’s MUE caps the code at 4 units per date of service.

95937 is a standalone code, so it is reported alongside nerve conduction studies 95907-95913 rather than bundled into them.

Each unit needs its own documented nerve, recording muscle, method, and CMAP result, backed by a signed physician interpretation.

CPT code 95937: official descriptor and what it covers

CPT code 95937 reports neuromuscular junction testing (repetitive stimulation, paired stimuli), each nerve, any 1 method. The code sits in the American Medical Association CPT code set, among the Medicine section’s neurology and neuromuscular procedures.

The test checks how well signals cross from nerve to muscle. A peripheral nerve receives a train of impulses, or paired stimuli, while the compound muscle action potential (CMAP) is recorded from a muscle it supplies.

A progressive drop in CMAP amplitude across the train, called a decrement, points toward myasthenia gravis. A marked rise after brief exercise or fast stimulation points toward Lambert-Eaton syndrome.

How the descriptor shapes billing

• Each nerve: one unit covers one nerve. Testing the ulnar and spinal accessory nerves in one session is two units.
• Any 1 method: repetitive stimulation and paired stimuli fall under the same code. Several rates or methods on one nerve still add up to one unit.
• Standalone code: 95937 carries no add-on designation, so it is reported in its own right rather than with a primary procedure.
• Unit limit: the Medicare medically unlikely edit (MUE) allows 4 units of 95937 per date of service.

Codes reported in the same session as 95937

Nerve conduction studies (95907-95913) and needle EMG are the codes most often reported with 95937, each under its own code. Conduction studies are coded by their total count, so a session with 11 or 12 studies is reported as 95912.

There is no limited or complete version of 95937, so code selection turns on counting rather than choosing between siblings. Check the current-year NCCI procedure-to-procedure table, via AAPC Codify or CMS, before adding modifier 59 or XS to any pair.

Counting units: a worked example

A patient with fatigable ptosis has repetitive stimulation of the ulnar, spinal accessory, and facial nerves. Each nerve is tested at 3 Hz at rest and again after 10 seconds of exercise.

The claim carries 95937 with 3 units, one per nerve. The post-exercise trials add no units, because they repeat the same nerves. If the session also includes six conduction studies, 95909 is reported for those as well. The breakdown below maps each nerve in the report to its line on the claim.

ICD-10 codes that support medical necessity for CPT 95937

Myasthenia gravis, Lambert-Eaton syndrome, and other myoneural disorders are the core ICD-10 codes that support 95937. Each Medicare Administrative Contractor (MAC) sets its accepted list in a Local Coverage Determination (LCD), so check the one for your jurisdiction.

When the study rules out a junction disorder, code the presenting sign that prompted it, such as ptosis or muscle weakness. Confirm that sign appears on your MAC’s covered list in the CMS Medicare Coverage Database before the claim goes out.

Documentation requirements for CPT code 95937

Every unit of 95937 must trace back to one documented, distinct nerve. Maintaining medical billing compliance for this code means the record shows these elements for each nerve billed.

• Clinical indication: the suspected disorder and the symptoms that prompted testing, such as fatigable weakness, ptosis, or diplopia.
• Nerve and recording muscle: each named anatomically, for example the spinal accessory nerve recorded from the trapezius.
• Method and settings: the stimulation rate in Hz and the number of stimuli in each train, or the paired-stimulus intervals.
• Results: the baseline CMAP amplitude and the percentage decrement or increment, stated as numbers.
• Exercise or rest trials: their timing and results, where they were performed.
• Interpretation: a signed report from the interpreting physician that links the findings to the diagnosis on the claim.

For submitting a clean claim, the units on the 95937 line should equal the number of nerves in the signed report. Matching the two before submission keeps the claim defensible on audit.

Modifiers for CPT code 95937

Modifier choice for CPT code 95937 depends on who owns the equipment and who interprets the study. Several nerves are billed as units on one line, not with a repeat-procedure modifier.

Bill the global code, with no modifier, when the practice owns the equipment and employs the interpreting physician. Never put 26 and TC on the same line from the same billing entity.

Medicare reimbursement for CPT code 95937

Medicare pays CPT code 95937 per unit under the Medicare Physician Fee Schedule (MPFS). The rate is the code’s relative value units (RVUs), adjusted for location, multiplied by the conversion factor.

For CY2026, CMS set two conversion factors: $33.5675 for qualifying APM participants and $33.4009 for other clinicians. Pull the current RVUs and your local rate from the CMS Physician Fee Schedule lookup tool before quoting a figure.

Pabau, the practice management and billing platform we build, sends 95937 claims in the 837P format through its Claim.MD integration. The electronic remittance advice then comes back to the same claim record.

Prior authorization and payer requirements

Medicare fee-for-service does not require prior authorization for CPT code 95937. Medicare Advantage and commercial plans set their own rules, so treat this list as a starting point.

• Medicare fee-for-service: no prior authorization, but the diagnosis must fit the MAC’s LCD and the record must support it.
• Medicare Advantage plans: requirements vary by plan. Check the plan’s authorization portal or provider line before scheduling.
• Commercial payers: many require authorization for electrodiagnostic studies, usually with documented symptoms of junction dysfunction.
• Unit limits: some payers apply their own limit on nerves per study, which can be lower than the Medicare MUE of 4.

Common denial reasons and how to avoid them

Most CPT code 95937 denials trace back to unit counts or diagnosis support. Structured denial management workflows help a billing team spot the pattern and fix it at the source. The adjustment reason code on the remittance shows which cause applied, and our guide to decoding denial codes explains each one.

• Units counted per train or per rate: several trials on one nerve were billed as several units. Bill one unit per nerve.
• Units above the MUE: Medicare denies more than 4 units of 95937 on one date of service, so confirm the count first.
• Unsupported diagnosis: the ICD-10 code is not on the MAC’s LCD list. Without a signed ABN, the patient cannot be billed for the denial.
• NCS dropped as bundled: a team that leaves off 95907-95913, believing 95937 includes them, forfeits payment for those studies.
• Nerves missing from the report: the claim shows more units than the signed interpretation lists. Match the two before submission.
• No signed interpretation: technician worksheets support the record but do not replace the physician’s report.
• Modifier 26 or TC mismatch: global billing when the physician only interpreted, or a split that does not match the payer contract.

How Pabau helps neurology practices bill CPT 95937

Electrodiagnostic labs often record nerve-by-nerve results on technician worksheets, then re-key a unit count into a separate billing system. That hand-off is where units drift away from the report and NCS codes get left off.

In Pabau, a custom form can capture each nerve, its recording muscle, the method, and the CMAP result in one structured note. The physician signs the interpretation in the same patient record, so the billing team counts units from the signed report.

Pabau’s claims management software then submits the claim through Claim.MD and tracks it to payment. When an ERA returns a denial, its reason code sits beside the original claim, so the biller can see which line was denied.

Bill every documented nerve, and only those

Pabau keeps the signed electrodiagnostic report, the unit count, and the claim on one patient record. Claims go out through Claim.MD, and the ERA comes back to the same claim. See how it fits a neurology billing workflow.

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Conclusion

Bill CPT 95937 by counting nerves, not stimulation trains, and report the session’s NCS and EMG codes alongside it. A practice that has treated 95937 as a complete study with bundled NCS has likely under-billed conduction studies and mis-counted units.

Pull a sample of recent junction studies and compare three numbers: nerves in the signed report, units on the claim, and NCS studies billed. Where they disagree, start with how the lab records its results. To see how Pabau keeps the report and the claim in step, book a demo with our team.

Continue your research

Counting nerve conduction studies for the same session? CPT code 95912 explains how NCS studies are counted across 95907-95913.

Adding needle EMG to the nerve conduction studies? CPT code 95886 covers the complete add-on study, reported per extremity with the NCS code.

Need to understand how clean claims reduce denial rates? Clean claim guidelines covers the elements every neurology claim needs before submission.

Want to see how electronic remittance advice works? Electronic remittance advice explained walks through ERA posting, CARC codes, and tracing denials to claim lines.

Preparing for a payer audit? Medical billing compliance guide covers audit preparation, documentation retention, and denial prevention for specialist practices.

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