Assistant-At-Surgery Services

by  Brittney Murdock, QCC, CMCS, CPC
January 6th, 2017

An "assistant at surgery" is a physician who actively assists the physician in charge of a case in performing a surgical procedure. The "assistant at surgery" provides more than just ancillary services.

Codes eligible for reimbursement for an assistant surgeon are designated by the Centers for Medicare and Medicaid Services (CMS) with minor modifications. Individual consideration may be made when there are extenuating circumstances. The primary surgeon needs to document the actions of the assistant surgeon with as much detail as possible, including documentation that the additional operative assistance was needed to perform the procedure. The primary surgeon must also authenticate the entry in the medical record.


Use modifier 80 when the assistant at surgery service was provided by a medical doctor (MD).

Use modifier 81 to identify minimum surgical assistant services, and is only submitted with surgery codes.

Use modifier 82 when the assistant at surgery service was provided by an MD and there was not a qualified resident available. Documentation must include information relating to the unavailability of a qualified resident in this situation.

Use the modifier "AS" for assistant at surgery services provided by a Physician Assistant (PA), Nurse Practitioner (NP), or Clinical Nurse Specialist (CNS). The provider must accept assignment. Medicare allows 85% of the 16% for the assistant at surgery services provided by a PA, NP, or CNS.

A MD/DO should not submit the "AS" modifier. This modifier is only valid for use by non-physician practitioners (NPP) when billing under their own provider number.

Billing for Assistant-At-Surgery

For assistant-at-surgery services performed by physicians, the fee schedule amount equals 16 percent of the amount otherwise applicable for the surgical payment.

Providers need to be aware that a non-restrictive assistant surgery payment indicator on the Medicare Physician Fee Schedule Database does not alone determine that Medicare will approve payment for an assistant at surgery service.

A/B MACs (B) may not pay assistants-at-surgery for surgical procedures in which a physician is used as an assistant-at-surgery in fewer than five percent of the cases for that procedure nationally. This is determined through manual reviews.

Medicare’s policies on billing patients in excess of the Medicare allowed amount apply to assistant-at-surgery services. Physicians who knowingly and willfully violate this prohibition and bill a beneficiary for an assistant-at-surgery service for these procedures may be subject to the penalties contained under §1842(j)(2) of the Social Security Act (the Act.) Penalties vary based on the frequency and seriousness of the violation. Go to and select the relevant section.

Assit Modifier information can also be found on the code lever under additional code information on the Find-A-Code website.

Visit for more information.


Assistant-At-Surgery Services. (2017, January 6). Find-A-Code Articles. Retrieved from

© InnoviHealth Systems Inc

Article Tags  (click on a tag to see related articles)

Publish this Article on your Website, Blog or Newsletter

This article is available for publishing on websites, blogs, and newsletters. The article must be published in its entirety - all links must be active. If you would like to publish this article, please contact us and let us know where you will be publishing it. The easiest way to get the text of the article is to highlight and copy. Or use your browser's "View Source" option to capture the HTML formatted code.

If you would like a specific article written on a medical coding and billing topic, please Contact Us.


innoviHealth Systems, Inc.
62 East 300 North
Spanish Fork, UT 84660
Phone: 801-770-4203 (9-5 Mountain)
free demo
request yours today
for any budget
sign IN
welcome back!

Thank you for choosing Find-A-Code, please Sign In to remove ads.