CMS Pub. 100-04, ch. 12, § 120.1

Nurse Practitioners and Clinical Nurse Specialists

(Rev. 2656, Issuance: 02-07-13, Effective: 02-19-13, Implementation: 02-19-13)

Medicare law at section 1833(a)(1)(O) of the Social Security Act authorizes payment for

services that NPs and CNSs furnish as an assistant-at-surgery. Specifically, when a NP

or CNS actively assists a physician in performing a surgical procedure and furnishes

more than just ancillary services, the NP’s and CNSs’ services are eligible for payment as

assistant-at-surgery services. For additional policy requirements concerning assistant-at-surgery services furnished by physicians and nonphysician practitioners, see chapter 12,

section 20.4.3 of the Medicare Claims Processing Manual, Pub. 100-04.

The A/B MAC (B) shall pay covered NP and CNS assistant-at-surgery services at 80

percent of the lesser of the actual charge or 85 percent of the 16 percent that a physician

is paid under the Medicare Physician Fee Schedule. Since physicians are paid at 16

percent of the surgical payment amount under the Medicare Physician Fee Schedule for

assistant-at-surgery services, the actual payment amount that NPs and CNSs receive for

assistant-at-surgery services is 13.6 percent of the amount paid to physicians.

Only the AS modifier must be reported on the claim form when a NP or CNS bills

assistant-at-surgery services.