Assistant Surgeon: Coding and Billing Aspect

An assistant surgeon assists the physician in performing a surgical procedure. Reimbursement for surgical assistant services is based on whether the assistant is a Physician or other health care professional. 

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Reimbursement for Assistant Surgeon services we should check eligibility like

  • whether the Assistant Surgeon is a Physician use with modifier 80, 81 or 82 or
  • another Health Care Professional use with modifier AS.
  • Payer would permit for additional reimbursement for surgical assistance for the reported procedure.
  • Need proper documents of assistance and role in performing surgery

Eligible for Reimbursement for Assistant at Surgery Service
• MD (Medical Doctor)
• DO (Doctor of Osteopathic Medicine)
• PA (Physician’s Assistant)
• NP (Nurse Practitioner)
• RNFA (Registered Nurse First Assistant)

Not Eligible for Reimbursement for Assistant at Surgery Services

  • Certified First Assistant (CFA)
  • Certified Surgical First Assistant (CSFA)
  • Certified Surgical Assistant (CSA)
    These provider types are also not payable for reimbursement as assistant surgeon by Medicare.


  • Physicians and certain non physician practitioners, such as nurse practitioners, physician assistants and clinical nurse specialists all are paid by Medicare Part B.
  • For Inpatient services, Diagnostic Related Group (DRG) and for Outpatient services, Ambulatory Payment Class (APC) covers payment prospective system for first assistant at surgery services performed by other providers, including certified surgical technologists and registered nurse first assistants.
  • The assistant surgeon must report the same codes as the surgeon. An exception  is when the surgeon bills a global code (e.g. maternity care). In that case, the assistant at surgery must bill the specific surgery-only code (e.g. delivery only).
  • The same clinical edits apply to the assistant surgeon as the primary surgeon.

The Assistant Surgeon Eligible List is based on the CMS National Physician Fee Schedule Relative Value File (NPFS) status indicators:-

  • 0 = Payment restriction for assistants at surgery applies to this procedure unless supporting documentation is submitted to establish medical necessity.
  • 1 = Statutory payment restriction for assistants at surgery applies to this procedure. Assistant at surgery may not be paid.
  • 2 = Payment restriction for assistants at surgery does not apply to this procedure. Assistant at surgery may be paid.
  • 9 = Concept does not apply.

Surgical Assistants who are Physician Assistants, Nurse Practitioners or Clinical Nurse Specialists should submit the identical procedure code as the primary surgeon, under the surgeon’s provider number, with the appropriate modifier to represent their service.

AS- PA, nurse practitioner, or clinical nurse specialist services for assistant at
80- Assistant surgeon
81- Minimum Assistant Surgeon
82- Assistant surgeon (when qualified resident surgeon not available)


  • Appended with modifier -80 or -82  will be reimbursed at 20% of the established fee.
  • Appended with modifier -81  will be reimbursed at 20% of the established fee.
  • Appended by a non-physician provider with modifier -81 appended will be reimbursed at 10% of the established fee.
  • Appended with modifier –AS  will be reimbursed at 10% of the established fee.

Multiple surgery fee reductions, bilateral adjustments, related within global adjustments, co-surgery adjustments, etc. may also apply before the final    allowable  amount for each line item.

One assistant surgeon is allowed per procedure code/surgery and second assistant surgeon will be considered only on the basis of a written documentation of medical necessity for the second assistant surgeon is submitted.


Modifier 80 Assistant Surgeon

This modifier is used by non-physicians assisting at surgery (e.g. Nurse Practitioners, Physician Assistants, Registered Nurse First Assistants, etc.).

Some Surgical procedure need assistance of another physician. That physician who assist would report the same surgical procedure as the operating surgeon. The assistant surgeon generally is present during the entire operation or a partial portion of the operation to provide assistance to the operating physician.

Modifier 81 Minimum Assistant Surgeon

When a minor problem is encountered during the operation that requires assistance of an assistant surgeon for a relatively short period of time, this is considered a minimum assistant surgeon.

Non-physicians (e.g. Nurse Practitioners, Physician Assistants, Registered Nurse First Assistants, etc.) can’t use.

Modifier 82 Assistant Surgeon (when qualified resident surgeon not available)

When a qualified resident surgeon is not available to assist the operating surgeon, so a physician assists the operating surgeon in that cases.

Modifier AS – Non-physician Assisting at Surgery

Medicare has approved the -AS modifier to report Physician Assistant (PA), Nurse Practitioner (NP), or Clinical Nurse Specialist (CNS) services for assistant-at-surgery, non-team member.


The most common misinterpretation of the assistant surgeon modifiers is to report PA or NP assistant surgical services.












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