The math Copy link
Start from the physician fee schedule amount for the code, locality, and setting, then take 85% of it. A $100.00 physician amount becomes $85.00. After the Part B deductible, Medicare pays 80% of that ($68.00) and the patient owes 20% ($17.00). As with any fee schedule payment, the calculation starts from the billed charge instead when that charge is lower. See it on a real code: CPT 99213.
Billing incident to a physician Copy link
When an NP or PA furnishes a visit incident to a physician’s service, the physician may bill it under their own NPI, and it is paid as the physician’s service. That only holds when every incident-to requirement in the Medicare Benefit Policy Manual is met. When they are not, the visit belongs under the practitioner’s own NPI, at 85%.
Assisting at surgery Copy link
An NP, PA, or CNS who assists at surgery bills with modifier AS. Medicare pays 85% of the 16% a physician assistant-at-surgery would receive, which works out to 13.6% of the surgery’s fee schedule amount. The assistant at surgery indicator decides whether the code pays an assistant at all.
NP and PA payment calculator Copy link
Enter the physician fee schedule amount for the code, locality and setting. For CPT 99213 in an office in Chicago, IL (Q4 2026), the physician amount is $99.63, so an NP or PA billing under their own NPI has an allowed amount of $84.69. For a surgery, choose “Assisting at surgery” and enter the surgery’s fee schedule amount: a physician assistant at surgery gets 16% and an NP, PA or CNS 13.6%.
- NP / PA / CNS allowed
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- Physician would be allowed
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- Medicare share (80%)
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- Patient coinsurance (20%)
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Assumes the Part B deductible is met, before sequestration. Whether the procedure pays an assistant at all depends on its assistant at surgery indicator.
Frequently asked Copy link
Does Medicare pay nurse practitioners less than physicians?
Yes, when the NP bills under their own NPI: the allowed amount is 85% of the physician fee schedule amount for the same service, locality, and setting.
Does the 85% rule apply to physician assistants?
Yes. Physician assistants, nurse practitioners, and clinical nurse specialists are all paid at 85% of the physician amount for services billed under their own NPI.
How is an NP paid for assisting at surgery?
At 85% of the 16% a physician assistant-at-surgery would be paid, which is 13.6% of the surgery’s fee schedule amount. The claim line carries modifier AS.
Sources Copy link
- CMS Medicare Claims Processing Manual (Pub. 100-04)
- CMS Medicare Benefit Policy Manual (Pub. 100-02)
Written from primary CMS sources—see how we source, compute, and verify everything on this site.
- Physician assistants, nurse practitioners, and clinical nurse specialists are paid for covered services at 80 percent of the lesser of the actual charge or 85 percent of what a physician is paid under the Medicare Physician Fee Schedule. —CMS Medicare Claims Processing Manual (Pub. 100-04)
- PA, NP, and CNS assistant-at-surgery services are paid at 85 percent of the 16 percent a physician is paid, which is 13.6 percent of the surgical payment amount, and must be billed with modifier AS. —CMS Medicare Claims Processing Manual (Pub. 100-04)
- When evaluation and management services are furnished incident to a physician’s service by a nonphysician practitioner, the physician may bill the CPT code that describes the service. —CMS Medicare Claims Processing Manual (Pub. 100-04)
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