Anaesthetic billing mistakes we see, and how to fix them.
Common anaesthetic claim problems include the wrong anaesthetic item for the operation, times not recorded, items lodged out of order, more than one basic unit item expected to pay, missed or doubled modifiers, same-day consults without the right detail, and patient or provider details that don’t match. Each has a simple habit that prevents it.
Eleven mistakes, and the habit that fixes each.
These are the problems we look for when an anaesthetist moves their billing to us. Each comes with the rule behind it, so you can check your own claims.
The wrong anaesthetic item for the operation
- The rule
- Each surgical procedure maps to its own anaesthetic item, and that item sets the base units. Similar operations can attract different items: a laparoscopic cholecystectomy is item 20706 (7 base units), an open cholecystectomy item 20790 (8 base units).
- The fix
- Get the surgeon’s MBS item number in writing before the list and match it to the anaesthetic item. Don’t reuse the previous case’s item because the operations look alike.
Start and end times not in the notes
- The rule
- Since 1 March 2022, time items 23010–24136 are payable only if the anaesthesia start and end times are recorded in writing. The times go in the patient notes, not on the claim.
- The fix
- Record both times on the anaesthetic record for every case, even short ones, so the claim can be supported if it’s queried.
Time units miscounted on long cases
- The rule
- Time is counted across the whole episode: one unit per 15 minutes or part of 15 minutes up to two hours, then one unit per 10 minutes or part after that. Check the current item descriptors on MBS Online.
- The fix
- Count from the recorded times, not memory, and recount any case over two hours. See the worked examples below.
Expecting every procedure’s base units to be paid
- The rule
- When several procedures are done under one anaesthetic, Medicare pays only the basic unit item with the highest value. The time item covers the whole episode.
- The fix
- List the basic unit items, but estimate and quote on the highest one plus total time, so the patient’s IFC matches what will be paid.
Items lodged in the wrong order
- The rule
- Services Australia rejects claims submitted out of order. The order is: basic unit items, one time item, physical status modifier, age modifier, in-hours emergency modifier, therapeutic and diagnostic items, and the after-hours emergency modifier last.
- The fix
- Build every claim from the same template in that order, and don’t reorder items by hand.
Physical status modifier missed or unsupported
- The rule
- The physical status modifiers are items 25000–25010, and only one is payable: the highest that applies.
- The fix
- Claim the modifier when the patient’s status justifies it, and write the reason in the record so it can be supported.
Age modifier missed, or the wrong age band used
- The rule
- Item 25013 applies to patients under 4 years; item 25014 to patients 75 or older. The previous age items, 25012 and 25015, were deleted on 1 May 2020.
- The fix
- Check the date of birth on every claim. It takes seconds and it’s easy to forget on a busy list.
Emergency modifiers doubled or mistimed
- The rule
- You can’t bill the in-hours emergency modifier (25020) and the after-hours emergency modifier (25025) for the same episode. The after-hours modifier applies when more than 50% of the emergency anaesthesia falls between 8pm and 8am on a weekday or at any time on a weekend or public holiday. It adds a 50% loading and needs the start, end and total times on the account.
- The fix
- Decide which one applies from the recorded times, list 25025 last, and show the times on the account.
Same-day attendances without the detail Medicare needs
- The rule
- If you bill an attendance on the same day as the anaesthetic, other than the pre-anaesthesia examination, Medicare needs the time of the attendance or confirmation it was a separate occasion. Pre-anaesthesia items 17615–17625 also require advanced surgery or complex medical problems and a written management plan in the notes.
- The fix
- Record the consult time and plan, and choose the 17610–17625 item by the time actually spent.
Patient or provider details that don’t match
- The rule
- Claims are rejected when the Medicare card has expired or doesn’t cover the patient (reason codes 208, 211), the card number is wrong (320), or the patient can’t be identified (217), and can be rejected when the provider number doesn’t match the location. You need a provider number for each location you work at.
- The fix
- Check the patient’s details before the day, and make sure each hospital has its own provider number on your claims.
Duplicates and rejected claims left unworked
- The rule
- Duplicates are rejected (codes 162, 703, 620). The 1-year lodgement limit applies to bulk-billed claims for services from 5 September 2025; patient and fund claims have 2 years, and services over 2 years old aren’t paid (code 111). Rejected claims can be corrected and resubmitted.
- The fix
- Keep one record of every case, reconcile it with what was billed each month, and work every rejection weekly.
Rules from Services Australia’s MBS billing for anaesthesia items (Nov 2025) and Relative Value Guide for anaesthesia billing, the Department of Health’s anaesthesia quick reference guides (1 May 2020, 1 March 2022) and Medicare reason codes.
Worked examples of time units.
| Anaesthesia time | First two hours | After two hours | Time units |
|---|---|---|---|
| 40 minutes | 3 units | — | 3 |
| 1 hour 10 minutes | 5 units | — | 5 |
| 2 hours | 8 units | — | 8 |
| 2 hours 25 minutes | 8 units | 3 units | 11 |
| 3 hours | 8 units | 6 units | 14 |
Part of a 15- or 10-minute block counts as a whole unit. For the full method of building a fee, see how to bill for anaesthetic services.
Fifteen minutes, once a month.
If you do your own billing, this short check helps catch the mistakes above before they cost you.
- Compare the cases in your own record with the cases billed. Anything missing or doubled?
- Pick five long cases and recount the time units from the recorded times.
- Check every case with a physical status or age modifier has the reason in the notes.
- Check every emergency case has one emergency modifier, not two, with times shown.
- List every rejected or queried claim, its reason code and the date you followed it up.
- Check every patient who paid a gap received a written estimate first.
Monthly billing self-check
One printable page with the checks above and the claim order.
Three ways a mistake costs you.
Less than the case was worth
A missed modifier or a short time count is paid as lodged, and nobody tells you what was missing.
Paid weeks later
A rejected claim waits for correction, and an old one can run out of time altogether.
Hard to defend
Records must be adequate and contemporaneous. A claim without times or reasons in the notes is difficult to support if it’s reviewed.
A surprised patient
A gap the patient wasn’t told about leads to disputes. Informed financial consent prevents it.
Checked before it’s lodged.
Every claim we lodge is quality-checked first, and every claim in a new anaesthetist’s first fortnight is checked by a senior biller. You submit your codes and times after each case; we raise the invoice within 48 hours, lodge and reconcile Medicare, Eclipse, fund, DVA and WorkCover claims, and follow up anything rejected or queried every week. You decide the codes. We check they go out right.
Fast Tracking charges 4.5% + GST of what we collect, with nothing charged on rejected or uncollected claims. See pricing.
Common questions
Why was my anaesthesia claim rejected?
Common causes include items lodged out of order, a basic unit item without exactly one time item, two emergency modifiers on one episode, patient details that don’t match Medicare’s records, or a provider number that doesn’t match the location. The reason code on the rejection tells you which, and Services Australia lets you resubmit a corrected claim.
Do I have to record anaesthesia start and end times?
Yes. Since 1 March 2022, the time items 23010 to 24136 are payable only if the anaesthesia start and end times are recorded in writing in the patient notes. The times aren’t sent with the Medicare claim, but they must be in the record.
What order do anaesthesia items go in on a claim?
Basic unit items first, then one time item, then the physical status modifier, the age modifier, the in-hours emergency modifier, therapeutic and diagnostic items, and the after-hours emergency modifier last. Services Australia rejects claims submitted out of order.
Which age modifiers apply to anaesthesia?
Item 25013 applies when the patient is under 4 years old, and item 25014 when the patient is 75 or older.
How long do I have to lodge a Medicare claim?
For bulk-billed services provided from 5 September 2025, claims must be lodged within 1 year. Patient and fund claims have 2 years, and Medicare rejects services more than 2 years old with reason code 111. Lodge and follow up promptly rather than relying on either limit.
Where this comes from
- Services Australia, MBS billing for anaesthesia items (updated 13 November 2025)
- Services Australia, Anaesthesia items: Relative Value Guide for anaesthesia billing (updated 1 March 2024)
- Department of Health, Quick reference guide: anaesthesia item changes (1 March 2022)
- Department of Health, Quick reference guide: anaesthesia age modifier (1 May 2020)
- Services Australia, Medicare reason codes and reducing claim rejections
- Health Insurance (General Medical Services Table) Regulations 2021 (Compilation No. 22, 1 July 2026; pre-anaesthesia items 17610–17625)
- Health Insurance (Professional Services Review Scheme) Regulations 2019, s 6 (adequate and contemporaneous records)
This page is general information for practitioners, not billing or legal advice. Check item descriptors on MBS Online before you bill. Rules checked 24 October 2026.
Rather not check every claim yourself?
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