01 · The short answer
Your fee comes from the surgeon’s list
Medicare works out your fee from the surgeon’s list. It applies the Multiple Operation Rule (MOR) to the operations you assisted at, and the result decides your item. Three terms come up throughout:
- Marked operation. A surgical item whose MBS description ends in “(Assist.)”.
- Abated total. The sum of your marked operations after the MOR reduces each fee by rank. Section 04 shows how.
- Established fee. The operation’s schedule fee, or your abated total where there is more than one. Some assistant items pay one fifth of it.
At or below $668.25: item 51300, $103.25.
Above $668.25: item 51303, one fifth of the abated total.
Every fee on this page is indicative at the time of writing
The MBS at 1 July 2026. Fees and schedules change. Check your fee schedules for the exact amounts.
02 · Which operations
Look for “(Assist.)” in the item description
Only Group T8 operations whose description carries “(Assist.)” pay a Medicare benefit for assistance. At an unmarked item, neither Medicare nor the health fund pays, however long the case or senior the assistant.
| Rule | What it means for the claim |
|---|---|
| Marked items only | No “(Assist.)” in the surgeon’s item means no assistant benefit. Check before the list. |
| Who can assist | A medical practitioner other than the surgeon, the anaesthetist or the assistant anaesthetist. |
| How many assistants | One benefit per operation, however many people assist. Two assistants share one fee. |
| Nurse practitioners | Separate rules apply (MBS note MN.33.1). Not covered here. |
03 · The two items
51300 below the threshold, 51303 above it
Both items are in Group T9, assistance at operations. The threshold and the fixed fee go up each July. The one fifth does not change. The item reference for 51300 and 51303 covers every Group T9 item.
| Item | When | Schedule fee | Medicare in hospital (75%) |
|---|---|---|---|
| 51300 | The operation’s fee, or your abated total, is $668.25 or less | $103.25, fixed | $77.45 |
| 51303 | The operation’s fee, or your abated total, is over $668.25 | One fifth of the abated total | 75% of that |
04 · The rule
100%, 50%, then 25% of each remaining item
When a surgeon does two or more Group T8 operations on a patient at the one time, Medicare does not add the fees. It ranks the items by fee and pays each by its rank (MBS note TN.8.2).
The item with the greatest schedule fee: 100%.
The next greatest: 50%.
Every other item: 25% each.
The sum is rounded up to the next 5 cents.
- Equal fees: one counts as the larger, so the order is still 100%, 50%, 25%.
- An item that only exists alongside another procedure is priced as if the rule always applies to it.
- A combination that has its own combined item is one item, not several.
- The rule does not apply between two surgeons operating independently on the same patient under the one anaesthetic. Each list is assessed on its own.
- A return to theatre the same day for a complication is a separate procedure, outside the rule. Note this on the claim.
05 · Applied twice
The surgeon’s total and yours are worked out separately
Medicare applies the rule twice. First over every item on the surgeon’s list, for the surgeon’s fee. Then over only the marked items you assisted at, for your abated total. Unmarked items drop out, and the rest are ranked again.
| Surgeon’s item | Marker | Surgeon’s total | Your total |
|---|---|---|---|
| A, $300 | (Assist.) | 100%: $300.00 | 100%: $300.00 |
| B, $250 | none | 50%: $125.00 | Left out |
| C, $200 | (Assist.) | 25%: $50.00 | 50%: $100.00 |
| D, $150 | (Assist.) | 25%: $37.50 | 25%: $37.50 |
| Total | $512.50 | $437.50, so item 51300 at $103.25 |
Item C moves from 25% on the surgeon’s list to 50% on yours, because B drops out. Your total can never be higher than the surgeon’s, since unmarked items are left out.
The threshold trap
The surgeon’s total can be over $668.25 while your abated total is not. Then the item is 51300 at the fixed fee, not 51303 at one fifth of the surgeon’s figure. A claim built on the surgeon’s total is adjusted or rejected. This happens most when the largest item on the list is unmarked.
06 · Worked examples
Four lists, four results
Example 1: one operation, above the threshold
Cholecystectomy with cholangiogram, item 30445, schedule fee $995.95, marked “(Assist.)”.
One item
Abated total = $995.95 (one item, at 100%).
$995.95 is above $668.25, so item 51303.
Fee = $995.95 ÷ 5 = $199.19
Medicare in hospital pays 75%, about $149.40. The health fund pays the rest, to its schedule.
Example 2: four operations, one unmarked
The TN.9.1 list from section 05. The surgeon’s total is $512.50. Your abated total is $437.50.
Four items, three marked
$437.50 is under $668.25, so item 51300.
Fee = $103.25
Not one fifth of $512.50.
Example 3: the threshold trap
Illustrative fees. The largest item on the list is unmarked.
Surgeon
X, $900, no marker: 100%, $900.
Y, $400, “(Assist.)”: 50%, $200.
Z, $300, “(Assist.)”: 25%, $75.
Total $1,175, over the threshold.
Assistant
Y, $400: 100%, $400.
Z, $300: 50%, $150.
Abated total $550, under it.
Item 51300, $103.25. Not $235, one fifth of $1,175.
Example 4: two marked operations, both counted
Cholecystectomy with cholangiogram, item 30445 ($995.95), and diagnostic laparoscopy, item 30390 ($263.15), both marked “(Assist.)”.
Two items
Abated total = $995.95 + ($263.15 × 50%) = $995.95 + $131.58 = $1,127.55, rounded up to the next 5 cents.
Item 51303 = $1,127.55 ÷ 5 = $225.51
07 · Special cases
Cases with their own rules
| Case | Rule | Source |
|---|---|---|
| Two surgeons operating independently | Treated as two operations. An assistant engaged by each surgeon, or by one, is paid as if they operated separately. | TN.9.1 |
| Abandoned surgery | The assistant fee is 50% of the Group T9 fee that would have applied. Claim that item and write “assistance at abandoned surgery” on the claim. | TN.8.5, item 30001 |
| Return to theatre the same day | A return for a complication is not normal aftercare and falls outside the rule. Note it on the claim as a separate procedure. | TN.8.2, TN.8.4 |
| Caesarean section | Item 51306, a fixed $149.25, where no marked operation is done with it. Item 51309 where one is: the Caesarean counts at $755.05 (the item 16520 fee) and is ranked with the marked operations under the rule. The fee is one fifth of that total. | TN.9.4 |
| Interventional obstetrics | Item 51312, one fifth of the established fee, for items 16606 to 16627. | TN.4.11 |
| Cataract surgery | Items 51315 ($326.05) and 51318 ($215.20), only where the conditions each lists are met. 51300 and 51303 do not apply. | TN.9.5 |
08 · Getting paid
Medicare pays 75% in hospital, the health fund the rest
For an admitted patient, Medicare pays 75% of the assistant’s schedule fee. The health fund pays the other 25%. If you bill under its no-gap or known-gap scheme, the fund also pays its own rate above the schedule. Under known-gap, the patient can be charged up to $500 per procedure. Setting the fee, fund schedules and informed financial consent are covered in the surgical assistant billing guide.
09 · Where claims go wrong
Six ways an assistant claim fails
- Assisting at an unmarked item. Neither Medicare nor the health fund pays. The claim is rejected.
- Claiming 51303 on the surgeon’s total. Your abated total counts only marked items. If it is $668.25 or less, the item is 51300, and the claim is adjusted or rejected.
- The surgeon’s items missing from your claim. Medicare needs the operations you assisted at to work out your abated total. Without them, 51303 cannot be priced.
- Two assistants each claiming. One benefit per operation. The second claim is rejected.
- The anaesthetist claiming as assistant. Not payable.
- Charging by time. Group T9 has no time element. The fee comes from the operations assisted at.
Common questions
- How is a surgical assistant fee calculated under the Multiple Operation Rule?
Medicare applies the Multiple Operation Rule (100%, 50%, then 25% for each item after that) to only the “(Assist.)” operations the assistant was present for. If that abated total is $668.25 or less, the item is 51300, $103.25 at 1 July 2026. Above it, item 51303 pays one fifth of the abated total.
- What is the item 51303 threshold in 2026?
$668.25 at 1 July 2026. If the operation’s fee, or the abated total of the operations assisted at, is over that, claim 51303. At or below it, claim 51300 at a fixed $103.25. Both amounts go up each July.
- Is the assistant fee one fifth of the surgeon’s total?
Not always. The assistant’s abated total counts only marked items, so it can be lower than the surgeon’s. The fee is one fifth of that figure, and only when it is over $668.25. If the surgeon’s list is over the threshold but the assistant’s is not, item 51300 applies at the fixed fee.
- Does the assistant fee include operations without “(Assist.)”?
No. An unmarked item pays no assistant benefit and is left out of the assistant’s total, even when it is the largest on the surgeon’s list.
- Can two doctors both claim for assisting at the same operation?
No. One benefit is paid per operation, however many people assist. Where two surgeons operate independently on the same patient, each operation is assessed on its own and an assistant at each can be paid.
- What does a surgical assistant get paid for abandoned surgery?
50% of the Group T9 fee that would have applied had the operation been completed (MBS note TN.8.5). Use that item and write “assistance at abandoned surgery” on the claim.
- Which item applies for assisting at a Caesarean section?
Item 51306, a fixed $149.25 at 1 July 2026, where no marked operation is done at the same time. Where one is, item 51309 pays one fifth of the total after the Multiple Operation Rule, with the Caesarean counted at $755.05 (the item 16520 fee) and ranked with the marked operations. A Caesarean with tubal sterilisation, item 35691, comes to $170.00.
FreshClaim for surgeons and assistants
FreshClaim works out the assistant item.
- 1
Both totals, worked out at entry
Enter the surgeon’s items. FreshClaim works out the surgeon’s total and yours, picks 51300 or 51303 and prices it before the claim is lodged.
- 2
Eligibility checked before the claim
Items without “(Assist.)” are flagged at entry, not after a rejection.
- 3
The surgeon’s list attached
The assistant claim carries the operations assisted at, so Medicare and the health fund can work out the abated total without a query.
- 4
Known-gap billing, handled before the list
Send the theatre list ahead of time. FreshClaim prepares the informed financial consent, issues the patient invoice and manages prepayment.
- 5
See where every claim stands
Each claim shows its status from capture to payment. Where a claim is rejected, FreshClaim investigates, corrects and re-lodges it.
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