How do I fix OHIP error code MN?

Count G264 and G265 services paid for the patient this calendar year. For blocks past 16 in the year, get a written recommendation from an independent expert as defined in the Schedule (J80) and bill G291 and G292 on an independent consideration basis. If you believe the decision is wrong, send a Remittance Advice Inquiry (RAI) through eSubmit, or on form 0918-84, within 7 months of the RA date, with supporting details.

When shouldn't I resubmit a MN claim?

The yearly limit was reached and you don't have an independent expert recommendation. The line is already on your RA. Question it with an RAI, not a new claim.

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Error code

MN — Maximum occipital nerve block sessions reached

Q: What does OHIP error code MN mean?

MN means the patient has reached the maximum occipital nerve block sessions. More first blocks need independent consideration (G291).

Nerve block limit reached

The patient has reached the maximum occipital nerve block sessions: G264 16 and G265 48 per calendar year.

What to do: For blocks past 16 in the year, get an independent expert's written recommendation and bill G291 and G292.

Code: MN
Description: Maximum occipital nerve block sessions reached

Explanation

Updated October 26, 2026

MN means the patient has reached the maximum occipital nerve block sessions. More first blocks need independent consideration (G291).

What it means

MN means the maximum number of occipital nerve block sessions has been reached.

G264 (first occipital block of the day) is limited to 1 per day and 16 per calendar year. G265 (each additional block) is limited to 3 per day and 48 per calendar year. First blocks beyond 16 in a year may be paid as G291 on an independent consideration basis with a written recommendation from an independent expert, and G292 for additional blocks (Schedule J80).

Common causes

More than 16 first occipital blocks billed as G264 in the calendar year
More than 1 G264 or 3 G265 on the same day

How to fix it

Count G264 and G265 services paid for the patient this calendar year.
For blocks past 16 in the year, get a written recommendation from an independent expert as defined in the Schedule (J80) and bill G291 and G292 on an independent consideration basis.
If you believe the decision is wrong, send a Remittance Advice Inquiry (RAI) through eSubmit, or on form 0918-84, within 7 months of the RA date, with supporting details.

Don't resubmit if

The yearly limit was reached and you don't have an independent expert recommendation.
The line is already on your RA. Question it with 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

Related codes: MA, MD, MY