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Error code

S6 — Initial procedure already billed - paid as subsequent procedure

Paid as subsequent procedure

The initial procedure was already claimed for this patient, so this one was paid at the lower subsequent procedure fee.

What to do: If the procedure really was a repeat, the rate is correct; bill the subsequent code next time.

Code
S6
Description
Initial procedure already billed - paid as subsequent procedure

Explanation

Updated October 26, 2026

S6 means the initial procedure was already claimed, so this one was paid as a subsequent procedure at the lower fee.

What it means

Code S6 means OHIP paid this line as a subsequent procedure because the initial procedure had already been claimed for the patient.

Some procedures have separate fees for the first (initial) service and later (subsequent) services. When an initial procedure is already on file, a repeat claim for the initial code is paid at the subsequent rate.

Common causes

  • The initial code was billed again for a follow-up procedure
  • Another physician already billed the initial procedure

How to fix it

  1. Check the earlier claim for the initial procedure.
  2. If the procedure really was a repeat, the subsequent rate is correct. Bill the subsequent code next time.
  3. If it was a new course of treatment that qualifies for a new initial fee under the listing's rules, 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 procedure was a repeat of one already claimed.
  • 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

Related codes: S9, D1

Sources