E401 – After Hours Premium - Night (00:00h - 07:00h)
OHIP Surgical Assists Code · Schedule of Benefits
A premium payable to surgical assistants and anaesthesiologists for cases that commence during the night period (00:00h to 07:00h). The premium increases the total fee (basic units plus time units) by 75%.
When to Use
- Use E401 when the surgical case officially commences between 00:00h and 07:00h to trigger the 75% premium on the base fee.
- Apply E401 in conjunction with C999B or C999C when providing surgical assistance or anaesthesia services during the night period.
Common Pitfalls
- Billing E401 for cases that commenced before midnight (e.g., 23:30h); in this scenario, E400 applies to the entire duration of the case, not E401.
- Failing to recognize that E401 is calculated only on the base fee, meaning it cannot be stacked as a percentage of other premiums like E420.
Billing Tips
- Ensure the case start time is clearly documented in the operative report, as this is the sole determinant for E401 eligibility versus E400.
Effective: April 1, 2026
After Hours
Premium
The premium is based on the time the case commences, not the time the assistant/anaesthesiologist starts their specific portion (unless they are the one starting the case).
If a case commences during the evening (E400) and continues into the night, the evening premium (50%) applies to the entire duration; the night premium (75%) only applies if the case actually starts after 00:00h.
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