Error code
DS — Not allowed - mutually exclusive code billed
Mutually exclusive code billed
This code can't be paid with another code billed for the patient, so OHIP paid the other one and refused this.
What to do: If the code that was paid best describes what you did, there is nothing to fix.
- Code
- DS
- Description
- Not allowed - mutually exclusive code billed
Explanation
Updated October 26, 2026
DS means this line wasn't paid because it can't be paid with another code billed for the patient. Check which code fits the service.
What it means
DS appears on the Remittance Advice (RA) when a fee code was not allowed because a mutually exclusive code was also billed. The Schedule of Benefits does not let both codes be paid together, so OHIP paid one and refused the other.
The refused line usually shows $0. The other code on the same patient is normally the one that was paid.
Common causes
- Two codes whose payment rules say they can't be paid together were billed for the same patient
- A service that is part of another billed service was also billed separately
- The same service was billed under two different codes
How to fix it
- Find the other code billed for the patient and read the payment rules for both in the Schedule of Benefits.
- If the code that was paid best describes what you did, there is nothing to fix.
- If the wrong code was paid and the refused one was correct, send a Remittance Advice Inquiry (RAI) through eSubmit, or on form 0918-84, within 7 months of the RA date, explaining the change.
- Update your billing so the two codes aren't billed together in future.
Don't resubmit if
- The Schedule says the two codes can't be paid together.
- The claim is already on your RA. A new claim for the same service will be treated as a duplicate. Use an RAI instead.
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