Anaesthesia claims are basic units + time units + extra units, multiplied by the anaesthesiologist unit fee of $15.96. The extra units — ASA class, BMI over 40, patient position, age, emergency — are separate E-prefix codes, and they are not all small: E017C for ASA IV is 10 units, or $159.60. The after-hours premiums are percentages on top of the whole anaesthetic fee, at 50% for evenings and 75% for nights.
IntelAGENT offers the eligible extra units on the case rather than leaving them to memory. See how →
Anaesthesia has the most mechanical claim structure of any specialty — units, extra units and percentages, with little judgement about which code applies — and precisely because it is mechanical, the losses come from omission rather than error.
The extra units and what they are worth
| Code | Description | Units | Amount |
|---|---|---|---|
| E016C | ASA V — moribund patient not expected to live 24 hours with or without operation | 20 | $319.20 |
| E017C | ASA IV — incapacitating systemic disease that is a constant threat to life | 10 | $159.60 |
| E025C | Unanticipated massive transfusion | 10 | $159.60 |
| E012C | Known or strongly suspected malignant hyperthermia, with full set-up and management | 5 | $79.80 |
| E020C | ASA E — emergency surgery commencing within 24 hours of operating room booking | 4 | $63.84 |
| E011C | Patient in prone position during surgery | 4 | $63.84 |
| E024C | Patient sitting, greater than 60 degrees upright | 4 | $63.84 |
| E018C | Adult aged 80 years and older | 3 | $47.88 |
| E022C | ASA III — severe systemic disease limiting activity but not incapacitating | 2 | $31.92 |
| E010C | Body mass index greater than 40 | 2 | $31.92 |
Unit values and the unit fee are the ministry's, from the anaesthesiologists' services part of the General Preamble. Basic units per procedure, how time units are counted, and the conditions on each extra unit are all in the current Schedule. Check it before billing an extra unit you have not used. These fees are from the Schedule effective July 1, 2026 (PDF).
Basic units, time units and the unit fee
The anaesthetic itself is paid as basic units for the procedure plus time units for its duration, and the unit count is then multiplied by a single dollar figure: the anaesthesiologist unit fee, $15.96. The assistant unit fee is $12.91. The basic units follow from the surgical procedure — they are printed in the Anae column beside each surgical listing in the Schedule — and the time units follow from the recorded anaesthetic start and end times.
A few anaesthetics have their own fixed basic unit count instead of taking it from the surgical listing. E032C, anaesthesia for colonoscopy or sigmoidoscopy, is 4 basic units plus time units. E023C, for ocular surgery, cystoscopy and examinations under anaesthesia, is 6 basic units plus time units.
Where this goes wrong is at the edges of the recorded time. Time units are claimed against the anaesthetic record, not the operating-room record or the surgeon's time, and a claim built from the wrong source under-counts. If your anaesthetic record and the OR schedule disagree, the anaesthetic record is what supports the claim.
The extra units are where the money is
Extra units get skipped because they feel small, and they are not all small. E017C for an ASA IV patient is 10 units, which at $15.96 a unit is $159.60 — more than the basic units of many procedures. E016C for ASA V is 20 units, or $319.20. One list with three ASA III patients, one ASA IV patient and one prone case carries 20 extra units, $319.20, for work that was already done and documented.
The extra units that get missed most:
- ASA class. E022C for class III at 2 units, E017C for class IV at 10, E016C for class V at 20. The class is on the anaesthetic record; it just has to make it onto the claim.
- BMI above 40. E010C, 2 units. Requires the BMI to be documented, which means it needs to be recorded at the time rather than reconstructed.
- Position. E011C for prone and E024C for sitting more than 60 degrees upright, 4 units each. Positioning is documented in the record and almost never reaches the claim.
- Emergency. E020C, 4 units, where surgery began within 24 hours of the operating room booking.
- Age. E018C, 3 units, for an adult aged 80 or older.
- Evening and night. E400C adds 50% and E401C adds 75% to the whole anaesthetic fee. These are percentages, not units, so on a long case they are the largest single addition to the claim, and they turn entirely on what time the case commenced.
A practical habit. Build the claim from the anaesthetic record rather than from the OR list. The record already contains the ASA class, the position, the BMI and the times — everything the extra units depend on. The OR list contains none of it.
H010A is not a Schedule of Benefits code
H010A does not appear anywhere in the Schedule of Benefits. It is a stipend code, submitted through the same claims channel as fee-for-service but paid under a separate ministry program and attributed to a stipend group number rather than to a fee.
That matters for two reasons. The first is that looking H010A up in the Schedule to find out what it pays or when it applies will not work — the terms are in the program agreement, which is the document to check. The second is that a stipend line does not settle like an ordinary claim, so a line that looks wrong on a Remittance Advice may be behaving exactly as intended. See reading a Remittance Advice for how to tell those apart.
What gets missed
-
Extra units, in bulk
The largest single loss in the specialty, and the one that compounds fastest, because it happens on most cases rather than on unusual ones.
-
Time units against the anaesthetic record
Rounding down, or billing scheduled time instead of actual time.
-
Evening and night percentages
E400C at 50% and E401C at 75%, and special visit premiums where you were called in — how those work.
-
H010A on covered dates
Easy to stop submitting a code that is not paid as a claim payment.
Billing anaesthesia in IntelAGENT
Anaesthesia is a unit calculation, not a code lookup: basic units, time units, extra units and the after-hours uplift, all against the same case.
- Extra units prompted, not remembered. The eligible extra units for a case are offered on the claim rather than recalled, which is the difference between billing five of them and billing two.
- Quantity handled correctly. Where a case carries multiples, the quantity is carried through to submission rather than being collapsed to one.
- Stipend codes. H010A is submitted with its stipend group number and tracked apart from fee-for-service, so a stipend line is not read back as a failed claim.
- Group and departmental billing. Anaesthesia departments that bill as a group get remittances split back to the rendering physician — groups and departments.
- Mobile entry between cases. Billing from the phone app in the OR corridor rather than from a stack of records at the end of the week, which is when the extra units get lost.
Three months free, then 0.25% of paid claims, capped at $39.99 a month. IntelAGENT has submitted OHIP claims since 2016 for more than 2,000 Ontario physicians.
Frequently asked questions
How is anaesthesia billed under OHIP?
As basic units for the procedure plus time units for its duration, plus extra units for patient and procedure factors — ASA class, BMI, patient position and patient age. The total unit count is multiplied by the anaesthesiologist unit fee, $15.96.
What are the E-prefix anaesthesia codes?
Most of them add extra units: E022C is ASA III at 2 units, E017C is ASA IV at 10 units, E016C is ASA V at 20, E010C a BMI over 40 at 2, E011C the prone position at 4, E020C an emergency case at 4 and E018C a patient aged 80 or older at 3. E400C and E401C are different — they are percentage premiums for evening and night anaesthetics.
What are E400C and E401C worth?
E400C adds 50% to the total anaesthetic fee when the case commences in the evening, 17:00h to 24:00h Monday to Friday, or during the day or evening on a Saturday, Sunday or holiday. E401C adds 75% when the case commences at night, 00:00h to 07:00h. It is the start time that qualifies the case, not its duration.
What do anaesthesiologists most often miss?
The extra units. ASA class, BMI, position and age are all on the anaesthetic record, and none of them is prompted by the base code, which is why they are the easiest thing in the specialty to leave off a claim. Time units under-claimed against the recorded anaesthetic time are second.