Remittance Advice · Payment-time (remittance)
OHIP explanatory code W4
Warning:-service location indicator code missing
What W4 means
The Ministry of Health’s official wording for W4 is: “Warning:-service location indicator code missing.”
This code appears as an explanatory code on your monthly Remittance Advice (RA). It means the claim was adjudicated — paid, reduced, or refused — for the reason below. A claim already on your RA generally shouldn't be blindly resubmitted; follow the suggested action.
How to fix W4
Warning only - the claim was processed, but the service location indicator (SLI) code was missing. Include the correct SLI on future claims.
Payment-time codes appear on the monthly Remittance Advice after adjudication. Some are informational, some explain a reduced or refused payment. Where you disagree with the outcome, the usual route is a Remittance Advice Inquiry or written inquiry — not resubmitting the same claim, which can create a duplicate.
Related codes
- VRVisit reduced premium not applicable
- VSDate of service was a Saturday, Sunday or statutory holiday
- VXComplexity premium not applicable to visit fee
- W3Warning: - Service date is older than 3 months
- X2Gastrointestinal (G.I.) tract includes cine and video tape
- X3Gastrointestinal (G.I.) tract includes survey film of abdomen
- X4Only one Bone Mineral Density (BMD) allowed within a 36 month period for a low risk patient
- X5Only one Bone Mineral Density (BMD) allowed within a 12 month period for a high risk patient
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Code meaning per Ontario Ministry of Health — Remittance Advice Explanatory Codes / Messages (March 2026). The suggested action is general information for Ontario physicians, not billing, legal, or tax advice — codes and rules change, so verify against the current Ministry of Health documents before relying on a claim.