Error code
S4 — Procedure fee reduced when paid with related surgery or anaesthetic
Reduced with related surgery
The procedure fee was reduced because it was paid together with a related surgical procedure or anaesthetic.
What to do: Check which surgery or anaesthetic it was paired with, and the procedure's listing for rules on billing them together.
- Code
- S4
- Description
- Procedure fee reduced when paid with related surgery or anaesthetic
Explanation
Updated October 26, 2026
S4 means a procedure fee was reduced because it was paid with a related surgery or anaesthetic on the same claim or day.
What it means
Code S4 means OHIP reduced the fee for a procedure because it was paid together with a related surgical procedure or anaesthetic. The Ministry gives no further detail.
A related rule in the Surgical Preamble: when a physician gives an anaesthetic, nerve block or other medication in conjunction with a procedure they perform on the same patient, the anaesthetic is not eligible for payment. The exception is a post-operative pain block lasting more than 4 hours, billed as G224 (SP5, paragraph 20).
Common causes
- A procedure that is part of, or related to, a surgery billed the same day
- An anaesthetic or block given by the physician who did the procedure
How to fix it
- Check which surgery or anaesthetic the reduced line was paired with.
- Check the procedure's listing and section preamble for rules on billing it with other procedures.
- If the procedure was unrelated to the surgery, send a Remittance Advice Inquiry (RAI) through eSubmit, or on form 0918-84, within 7 months of the RA date.
Don't resubmit if
- The claim is already on your Remittance Advice. Use an RAI, not a new claim.
How APEX handles it
APEX reads your error reports and remittance advice from MCEDT and lists claims rejected with this code in its Correction Centre for you to correct and resubmit. See how APEX works · Pricing