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Error code

MS — Maximum sleep studies reached for this period

Sleep study limit reached

The maximum sleep studies for this period was reached, by you or another physician; more need Ministry prior approval.

What to do: Check the sleep study limits (Schedule J107 to J110) and which studies were already paid at any facility.

Code
MS
Description
Maximum sleep studies reached for this period

Explanation

Updated October 26, 2026

MS means the maximum sleep studies for this period was reached, by you or another physician. More need MOH prior approval.

What it means

MS means the maximum number of sleep studies allowed in a set period, by one or more physicians, has been reached.

Sleep studies have limits. Studies past a limit are not insured unless prior approval to exceed it was obtained from the Ministry. For example, only one initial diagnostic study is paid per patient per lifetime (Schedule J107 to J110).

Common causes

  • A study done after the limit was reached without prior approval
  • A second initial diagnostic study billed instead of a repeat or therapeutic study

How to fix it

  1. Check the sleep study limits in the Schedule (J107 to J110).
  2. Check which studies were already paid for the patient, at any facility.
  3. If the study met a reason for exceeding the limit, check whether prior approval was obtained.
  4. 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 limit was reached and no prior approval was obtained.
  • 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: MY, M4

Sources