CurrentUnitedHealthcarePolicy 2025R9038A

Assistant-at-Surgery reimbursement on CMS 1500

Defines UnitedHealthcare Medicare Advantage reimbursement rules for Assistant-at-Surgery services billed on the CMS 1500 form and who may bill as assistants (physicians vs non-physician health care professionals). Applies to network physicians and other qualified health care professionals providing services to UnitedHealthcare Medicare Advantage enrollees.

Policy Summary

PayerUnitedHealthcare

PolicyAssistant-at-Surgery reimbursement on CMS 1500

Policy CodePolicy 2025R9038A

Change TypeNo material change indicated

Effective Date

Next Review Date

Key ActionReport the AS modifier when a PA/NP/CNS performs assistant-at-surgery services and expect reimbursement per Medicare-based rules (PA ~13.6% of physician amount; physician assistants 16% for physicians).

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

16%physician assistant reimbursement rate

13.6%PA typical payment % of physician

Oneassistants reimbursable per procedure

0,1,2NPFS indicators referenced

Assistant-at-Surgery Reimbursement Criteria

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Assistant-at-Surgery reimbursement criteria

Covered when the conditions below are met:

ALL of the following

NPFS indicator rules
- NPFS Assistant-at-Surgery indicator 2: Procedures with indicator 2 are reimbursable for an assistant-at-surgery (only one assistant reimbursable per procedure).
- NPFS Assistant-at-Surgery indicator 1: Procedures with indicator 1 are not reimbursable for assistant-at-surgery services when billed with assistant modifiers (80, 81, 82, AS).
- NPFS Assistant-at-Surgery indicator 0: Procedures with indicator 0 are conditionally reimbursable and require clinical documentation to establish medical necessity for assistant-at-surgery payment review.

Provider type and payment

If the assistant-at-surgery is a Physician (MD/DO) and the service is eligible, reimbursement is 16% of the Allowable Amount; physician assistants should submit the identical procedure code(s) as the primary surgeon with modifier 80, 81 or 82.
If the assistant-at-surgery is a Health Care Professional (PA, NP, CNS), reimbursement follows Medicare Claims Processing Manual Chapter 12 §110.2: PA services reimbursed at 80% of the lesser of actual charge or 85% of the physician payment, resulting in 13.6% of the physician surgical payment amount; the AS modifier must be reported.

Exclusions and billing notes

Surgical technicians are not eligible to report modifier AS; their assistance is included in facility reimbursement and is not separately reimbursable.
Other nonphysician categories not recognized as Medicare providers cannot bill independently for assistant-at-surgery services.
If an Assistant-at-Surgery submits multiple procedure codes, multiple procedure reductions will apply.
No exceptions are made to allow reimbursement based solely on hospital bylaws or teaching hospital status; NPFS indicators determine assistant-at-surgery benefits.

Modifiers and NPFS Indicators

Relevant modifiersModifier

AS	Modifier to indicate assistant-at-surgery when a PA, NP, or CNS served as assistant
80, 81, 82	Modifiers used to indicate a physician assistant-at-surgery

NPFS assistant-at-surgery indicators

Indicator 2Reimbursable — procedures with NPFS Assistant‑at‑Surgery indicator 2 are considered reimbursable for an assistant‑at‑surgery (only one assistant reimbursable per procedure).

Indicator 1Not reimbursable — procedures with NPFS Assistant‑at‑Surgery indicator 1 are not reimbursable for assistant‑at‑surgery services when billed with assistant modifiers (80, 81, 82, AS).

Indicator 0Conditionally reimbursable — procedures with NPFS Assistant‑at‑Surgery indicator 0 require clinical documentation and will be reviewed for assistant‑at‑surgery eligibility before payment.

Billing and Authorization Notes

Prior Authorization

Prior authorization note — none specified

UnitedHealthcare's Medicare Advantage reimbursement policies do not include notations regarding prior authorization requirements. UnitedHealthcare Medicare Advantage may modify this reimbursement policy at any time to comply with changes in CMS policy and other national standard coding guidelines by publishing a new version of the reimbursement policy on its website. For specific enrollee benefit coverage or prior authorization details, contact the customer service number on the back of the member ID card or refer to CMS/local carrier guidance.

Billing Rule

Multiple procedure billing

If an Assistant-at-Surgery submits multiple procedure codes, multiple procedure reductions will apply. Ensure billing reflects only allowable assistant-at-surgery services: only one Assistant-at-Surgery is reimbursable for procedures with an Indicator of 2 on the National Physician Fee Schedule. When an Assistant-at-Surgery is a Physician, submit the identical procedure code(s) as the primary surgeon with modifier 80, 81, or 82; when the assistant is another qualified health care professional, use modifier AS. Multiple procedure reimbursement adjustments will be applied per standard multiple-procedure rules.

Only one Assistant-at-Surgery reimbursable for procedures with NPFS Indicator 2.
Physician assistants-at-surgery: use modifier 80, 81, or 82 and submit identical procedure code(s) as the primary surgeon.
Non-physician assistants-at-surgery: use modifier AS.
Multiple procedure reductions will be applied when multiple procedure codes are submitted.

Key Definitions

Allowable Amount

DefinitionThe dollar amount eligible for reimbursement to the physician or other qualified health care professional on the claim (examples: contracted rate, reasonable charge, or billed charges as applicable).

Determination for percent/discount contractsFor percent of charge or discount contracts, the Allowable Amount is the billed amount less the discount. (Applies when relevant to the contract type.)

Role in payment calculationAssistant‑at‑surgery reimbursement percentages (e.g., 16% for physicians) are applied to the Allowable Amount to determine payment.

Assistant-at-Surgery/Assistant Surgeon

Who qualifiesA physician (MD or DO) or other qualified health care professional who assists the physician performing a surgical procedure.

Billing implicationAssistant‑at‑surgery services must be reported with appropriate assistant modifiers (e.g., 80, 81, 82, AS) when applicable; reimbursement follows NPFS indicator guidance.

LimitationsOnly one assistant‑at‑surgery is reimbursable per procedure when allowed by NPFS indicator 2; hospital bylaws do not create exceptions to NPFS‑based determinations.

Health Care Professional

Physician Assistant (PA)A non‑MD/DO health care professional (physician assistant) recognized in this policy as a Health Care Professional; when eligible, PA assistant‑at‑surgery services follow Medicare reimbursement rules and require reporting of the AS modifier.

Registered Nurse (RN)A non‑MD/DO registered nurse is considered a Health Care Professional in the policy definition but is not described as independently billable for assistant‑at‑surgery outside recognized PA/NP rules.

Nurse Practitioner (NP)A non‑MD/DO nurse practitioner is included in the Health Care Professional definition; reimbursement for assistant‑at‑surgery by non‑physician practitioners follows Medicare policy and modifier reporting requirements.

Same Individual Physician or Other Qualified Health Care Professional

DefinitionThe same individual rendering health care services who reports the same Federal Tax Identification Number.

Use in claimsIdentifies when services are furnished by the identical provider (same person) for purposes of billing and attribution on the claim.

Distinct from organizational billingDistinguishes an individual provider reporting under a single Federal Tax ID from separate individuals or entities for reimbursement determinations.