How do I fix OHIP error code M1?

Check the patient's billing history for this code over the limit period. Check the code's limit in the Schedule of Benefits. If a different code correctly describes the service you provided, bill that code. Resubmitting the same code will not be paid. If you believe OHIP applied the limit wrongly, submit a Remittance Advice Inquiry (RAI) within seven months of the remittance advice date.

When shouldn't I resubmit a M1 claim?

You would be resubmitting the same code for the same service; it will hit the same limit. The limit was legitimately reached and no other code fits the service. The remittance advice is more than seven months old, for an inquiry.

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Error code

M1 — Maximum fee or number of services reached (any provider)

Q: What does OHIP error code M1 mean?

M1 on your remittance advice means OHIP already paid the maximum for this service, to you or another provider, so the line was reduced or not paid.

Maximum already reached

The maximum fee or number of services for this code was already paid, to you or another provider, so this line was reduced or unpaid.

What to do: Check the patient's history and the code's limit; later services may need a companion code, such as K033A after K013A.

Code: M1
Description: Maximum fee or number of services reached (any provider)

Explanation

Updated October 26, 2026

M1 on your remittance advice means OHIP already paid the maximum for this service, to you or another provider, so the line was reduced or not paid.

What it means

M1 is a remittance advice explanatory code, not an Error Report rejection. OHIP processed the claim but applied a limit. The Ministry's wording is that the maximum fee or maximum number of services has been reached by the same or any provider.

Many fee codes in the Schedule of Benefits have limits, such as once per patient per year or a set number of units per year. Once the limit is used up, further claims for that code pay less or nothing. Some codes have a companion code for later services. For example, after the first three K013A counselling units for a patient in a year, further counselling is billed as K033A.

Common causes

You already billed the code's limit for this patient earlier in the period.
Another physician, such as a walk-in clinic or the patient's other doctor, billed the limited service first.
The limited code was billed when the Schedule of Benefits has a different code for further services.

How to fix it

Check the patient's billing history for this code over the limit period.
Check the code's limit in the Schedule of Benefits.
If a different code correctly describes the service you provided, bill that code. Resubmitting the same code will not be paid.
If you believe OHIP applied the limit wrongly, submit a Remittance Advice Inquiry (RAI) within seven months of the remittance advice date.

Don't resubmit if

You would be resubmitting the same code for the same service; it will hit the same limit.
The limit was legitimately reached and no other code fits the service.
The remittance advice is more than seven months old, for an inquiry.

How APEX handles it

For unpaid family practice M1 lines, APEX proposes an alternative code in a few common cases: K013A to K033A, P005A to P004A, E079A to K039A with Q042A, and K030A or Q040A to A007A. If the service date is already stale-dated, APEX sends the correction to the Ministry as a spreadsheet request rather than a claim file, and only while the remittance advice is within seven months. See how APEX works · Pricing

Related codes: A3H, AC1, M4, MY