How do I fix OHIP error code AT4?

Find the tracking code on the claim that isn't on the Ministry's allowed list. Remove it from the virtual-care claim, keeping the virtual service and its K300A or K301A. If the visit was in person, remove the modality indicator instead; the Ministry says in-person services shouldn't carry one. If the patient had both an in-person and a virtual service that day, bill them on separate claims. Resubmit the corrected claim. Resubmit within three months of the service date if you can. If that window has passed but the claim was first submitted on time, use the Ministry's stale-dated resubmission process: one stale-dated claim file through MCEDT, then an email to ClaimsManagement@ontario.ca with the Error Reports showing the original submission date.

When shouldn't I resubmit a AT4 claim?

The tracking code and modality indicator are still on the same claim. It will reject again.

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Error code

AT4 — Modality Not Allowed

Q: What does OHIP error code AT4 mean?

AT4 means a virtual-care claim (K300A video or K301A phone) carries a tracking code that isn't allowed with a modality indicator.

Tracking code not allowed virtually

The virtual care claim (K300A or K301A) carries a tracking code that isn't on the Ministry's allowed list for virtual claims.

What to do: Remove the tracking code that isn't allowed, keep the virtual service and its modality indicator, and resubmit.

Code: AT4
Description: Modality Not Allowed

Explanation

Updated October 26, 2026

AT4 means a virtual-care claim (K300A video or K301A phone) carries a tracking code that isn't allowed with a modality indicator.

What it means

Since December 1, 2022, virtual care claims carry a modality indicator: K300A for video or K301A for telephone, on the same claim and service date as the virtual service. Only certain tracking codes may sit on a claim with a modality indicator.

The Ministry's virtual care bulletin lists the allowed tracking codes: Q006A, Q011A, Q020A, Q021A, Q130A, Q131A, Q132A, Q133A, Q140A, Q141A and Q142A. If a claim has any other tracking code on the same service date as a modality indicator, it rejects with AT4.

Common causes

A tracking code not on the allowed list, such as a roster enrolment code, added to a virtual visit claim
An in-person service and a virtual service for the same patient and date put on one claim
A modality indicator left on a claim for a visit that was really in person

How to fix it

Find the tracking code on the claim that isn't on the Ministry's allowed list.
Remove it from the virtual-care claim, keeping the virtual service and its K300A or K301A.
If the visit was in person, remove the modality indicator instead; the Ministry says in-person services shouldn't carry one.
If the patient had both an in-person and a virtual service that day, bill them on separate claims.
Resubmit the corrected claim. Resubmit within three months of the service date if you can. If that window has passed but the claim was first submitted on time, use the Ministry's stale-dated resubmission process: one stale-dated claim file through MCEDT, then an email to [email protected] with the Error Reports showing the original submission date.

Don't resubmit if

The tracking code and modality indicator are still on the same claim. It will reject again.

How APEX handles it

For some group billing setups, APEX treats AT4 caused by the Q200A enrolment code as an automatic fix: it rebuilds the claim without Q200A for review. Other AT4 claims appear in the Correction Centre as needing your input. See how APEX works · Pricing

Related codes: AT1, AT2, AT3, B1, B2