Clinical Billing Series

Surgical Assistant Billing: Fees, Rebates & Pricing Decisions

How the Surgical Assistant Fee Is Calculated

Your MBS schedule fee as a surgical assistant is 20 % of the surgeon's Multiple Operation Rule (MOR) total for that procedure. Two item numbers govern this depending on where that total lands relative to the current threshold of $651.30 — subject to annual MBS indexation:

Item 51300 — MOR total at or below the threshold ($651.30) — fixed fee of $100.65
Item 51303 — MOR total above the threshold — fee is MOR total × 20 %

Step 1 — Calculate the surgeon's MOR total

When a surgeon performs multiple surgical items in the same operation, Medicare applies a tiered reduction to each subsequent item. Your assistant fee is based on the blended MOR total — not the highest single item alone.

Multiple Operation Rule

// Multiple Operation Rule
Item 1 — highest schedule fee → paid at 100 %
Item 2 — next highest → paid at 50 %
Item 3+ — all remaining → paid at 25 % each

Step 2 — Apply the correct assistant item

Once the MOR total is known, the applicable item number is determined by whether it clears the threshold.

Example — three items: $1,500 / $900 / $600

// At or below threshold → item 51300 (fixed fee)
MOR Total ≤ $651.30 → $100.65 (subject to indexation)

// Above threshold → item 51303 (scaled fee)
MOR Total > $651.30 → MOR Total × 20 %

// Example: three items — $1,500 / $900 / $600
MOR Total = $1,500 + $450 + $150 = $2,100
Item 51303 = $2,100 × 20 % = $420.00

Step 3 — How fund schedules are derived

All health fund no-gap schedule fees are derived from this initial MBS calculation — the item 51300 or 51303 figure is the starting point from which the fund's no-gap rate is set. A further out-of-pocket amount is billable to patients of up to $500 above the fund's known-gap schedule. Beyond that ceiling, funds revert to paying only up to the Medicare schedule fee, with the patient liable for any amount above that point.

Component	Calculation	Example — MOR total $2,100
Surgeon's MOR total	Items at 100% / 50% / 25%	$2,100
Your schedule fee — item 51303	MOR total × 20%	$420
Medicare benefit	Your schedule fee × 75%	$315
PHI fund benefit (no-gap)	Your schedule fee × 25%	$105
Total rebate at no-gap	Medicare + PHI	$420
Patient out of pocket at no-gap	Your fee − total rebate	$0

Co-claim eligibility — check before billing

Not all surgical items carry assistant co-claim eligibility. If the principal item does not permit an assistant claim, there is no MBS benefit and no fund contribution — regardless of the patient's level of cover or whether an assistant was present. Billing against an ineligible item will result in claim rejection; this is not a recoverable gap. Always verify assistant eligibility at the item level before generating an invoice.

The Fund Rebate: What It Covers and When

When a privately insured patient is admitted to a private hospital, their fund is obligated to pay their gap — up to the MBS schedule fee — for an approved assistant item. However, not all surgical items carry assistant co-claim eligibility. If the principal item does not permit an assistant claim, there is no MBS benefit and no fund contribution.

No-gap

You charge at or below the fund's no-gap schedule fee. The patient pays nothing. The fund covers the full gap. Administratively simple with no IFC complexity — but caps your income at their scheduled rate.

Known-gap

You charge up to the fund's known-gap schedule fee — the same as the no-gap rate in most cases, with the notable exceptions of HCF and BUPA who set their own known-gap schedule fees — plus a maximum patient gap of $500 per procedure. The $500 limit applies across the entirety of the procedure, not per item. The patient consents to this gap before treatment. Funds pay their portion; the patient pays the known gap directly to you.

A minority of funds — typically lower-tier or restricted access products — do not participate in the Medical Gap Scheme. For these patients, any amount above the Medicare benefit becomes an out of pocket, even if you intend to charge only a known gap. Always verify fund participation before quoting patients, or ask your patients to verify with their fund personally to confirm their own level of cover.

Beyond the $500 known-gap ceiling

If you charge more than $500 above the fund's known-gap schedule, the fund reverts to paying only up to the Medicare schedule fee. The patient is liable for everything above that point — which can be substantially more than anticipated if the gap was presented without this nuance being explained.

What Should You Charge?

Your fee decision sits along a spectrum from no-gap through to an uncapped out-of-pocket arrangement. Each point carries different implications for your income, administrative burden, and your relationship with patients and the referring surgeon.

Billing mode	Your fee	Patient pays	Your income	IFC burden
No-gap	Fund no-gap schedule	$0	Fund schedule fee	Minimal
Known-gap	Known-gap schedule + up to $500	Up to $500	Schedule + gap	Moderate
Out of pocket	Any amount	Your fee minus rebate	Your set fee	High

Approximate fee benchmarks

Below the MOR threshold, item 51300 applies at a fixed rate. Above it, the fee scales with the MOR total. The Medicare benefit is 75 % of your schedule fee in both cases.

Procedure type	Surgeon's MOR total	Your schedule fee	Medicare benefit (75%)	Max known-gap
Minor / below threshold	≤ $651.30	$100.65 (item 51300)	$75.50	+ $500
Moderate (e.g. laparoscopy)	$800 – $1,200	$160 – $240	$120 – $180	+ $500
Major (e.g. bowel resection)	$1,500 – $2,500	$300 – $500	$225 – $375	+ $500
Complex / cardiac / spinal	$2,500 – $4,000+	$500 – $800+	$375 – $600+	+ $500

Rule of thumb for patient conversations

At the no-gap schedule fee, patient cost is zero (assuming adequate cover). At a known-gap, the assistant's gap is best understood in relation to the surgeon's — if the surgeon charges a $500 gap, the assistant might charge $100, or both parties may agree on a predetermined structure in advance. The specific amount matters less than alignment: the patient's expectations must be consistent with what the surgeon has already communicated. A misunderstanding between any party — even over a modest gap — creates friction that reflects on the entire treating team. At an out-of-pocket rate, the patient pays your fee minus the total rebate — which for a major procedure could comfortably exceed $500–$1,000.

Key Considerations When Planning to Charge an Out-of-Pocket Fee

Out-of-pocket billing is legitimate when genuinely justified — but it requires a clear process. Skipping any step produces the highest rate of disputed invoices, formal complaints, and bad debt in specialist practice.

Provide a written quote — Before any service is rendered, give the patient a written quote stating your fee, the expected Medicare and fund benefits, and their out-of-pocket cost. This must be prospective and specific.
Obtain and document informed financial consent — Send the patient a formal IFC document and retain a signed copy or a timestamped record of acceptance. Verbal consent without documentation is not sufficient for debt recovery or complaint defence.
Invoice and collect payment prior to the day of procedure — Issue your invoice and take payment in advance. Pre-collection removes the risk of non-payment after the fact and settles the financial relationship before the clinical one begins.
Have a clear policy for procedures that do not eventuate — Decide in advance whether collected funds are retained as a cancellation fee (if disclosed in your IFC) or released back to the patient in full. Communicate this clearly at the time of consent.

A Practical Framework

Treat the schedule fee as your baseline, not your ceiling. The real question is whether the clinical complexity and time involved justify the administrative overhead and patient impact of charging above it.

Working through your fee decision

Start with the surgeon's MOR total — your schedule fee is 20% of this (item 51303), or $100.65 (item 51300) below the threshold
Decide if no-gap is acceptable for this case type — zero admin, high collection rate
If complexity justifies more, apply a known-gap up to $500 — your maximum straightforward uplift
If you routinely charge above known-gap, build a fee schedule by procedure type and publish it
For out-of-pocket: calculate patient cost as Your Fee − (Medicare benefit + fund benefit) and quote this figure explicitly
Never assume the fund pays gap — verify, or have the patient verify their gap scheme participation

Simplifying IFC

IFC is the most friction-heavy part of surgical assistant billing. You're often a late addition to the team, which creates a structural challenge: consent must be prospective, but your involvement is sometimes confirmed retrospectively.

What IFC must include

For any out-of-pocket or known-gap situation, your IFC must state: your name and provider number, the expected item numbers, your fee, the expected Medicare benefit, the expected fund benefit, and the patient's estimated out-of-pocket cost. Ideally, the patient should have the opportunity to ask questions and to seek a second quote.

How to simplify it

Strategy 1 — Fee schedule card

Publish a simple one-page fee schedule grouped by procedure category. Give it to the surgeon's rooms to distribute at booking — consent is effectively prospective without any day-of-surgery scramble.

Strategy 2 — Phone consent with documentation

For last-minute additions, call the patient the evening before, provide the fee verbally, then follow up with an SMS or email confirmation. This creates a timestamped record and satisfies the spirit of prospective consent.

Strategy 3 — Default to known-gap for standard elective work

Reserve out-of-pocket billing for high-complexity or long-duration cases where you can genuinely justify it and provide consent in advance. Known-gap is straightforward to communicate and easy for patients to accept.

Simplifying the arithmetic for patients

Patients struggle with fund rebate calculations. Make it concrete: "Medicare and your fund will cover $X. My fee is $Y. You will pay $Z." Three numbers. Build a lookup table in your billing system so these figures generate automatically at time of booking.

Impacts on Patient, Surgeon, and Your Income

The Patient

Out-of-pocket costs for surgical assistance are often a genuine surprise. Most patients anticipate a surgeon fee — far fewer expect a separate assistant bill. Unexpected invoices generate complaints and delayed payment. Transparency at booking eliminates almost all downstream conflict.

The Surgeon

The principal surgeon is indirectly exposed to your pricing decisions. If your gap creates friction or complaint, they hear about it — and may quietly replace you on future lists. Communicating your approach to the surgeon in advance preserves the professional relationship.

Your Income

A full list of four moderate-to-major cases might yield $1,200–$2,400 at schedule fees. Known-gap adds up to $500 per procedure — meaningful over a full list. However, the collection rate on out-of-pocket bills is materially lower; factor this into your effective fee calculation.

The Ethical Dimension

Surgical assistance is often not elective for the patient — they need the surgery, and you are part of the team. The strongest justification for out-of-pocket billing is genuine clinical complexity, not the absence of a fund network agreement.

Summary — The Practical Decision Tree

Standard elective case, insured patient — No-gap or known-gap. Simple. Low admin. High collection rate.
Complex or long-duration case with advance notice — Known-gap or modest OOP with documented IFC.
Uninsured patient — Medicare benefit only regardless of your fee; factor this in before quoting.
Unplanned or emergency assist — Bill at schedule fee; no time for proper IFC justifies conservative billing.
Supra-specialist or revisional surgery — Out-of-pocket justified; ensure IFC is in writing before the case proceeds.
Any doubt about gap scheme participation — Verify before quoting, or have the patient verify with their fund directly.