How do I fix OHIP error code AH8?

Get the hospital's master number and the patient's admission date from the hospital record for this stay. Enter both on the claim and check that the admission date is the one for this stay. Resubmit the corrected claim 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 AH8 claim?

You can't confirm the admission date or master number. Sending a guess will reject again.

< Error codes

Error code

AH8 — Invalid admission date and/or hospital number

Q: What does OHIP error code AH8 mean?

AH8 means the admission date or hospital (master) number on an in-hospital claim is invalid or missing. Correct both and resubmit.

Hospital details invalid

The admission date, the hospital master number, or both are invalid or missing on this in-hospital claim.

What to do: Get both from the hospital record for this stay, enter them on the claim, and resubmit.

Code: AH8
Description: Invalid admission date and/or hospital number

Explanation

Updated October 26, 2026

AH8 means the admission date or hospital (master) number on an in-hospital claim is invalid or missing. Correct both and resubmit.

What it means

AH8 means OHIP rejected the claim because the admission date, the hospital number, or both, are invalid. In-hospital services need the hospital's master number on the claim, and in-patient services also need the admission date. The matching Remittance Advice message (H8) says the hospital number and/or admission date is required for an in-hospital service.

The Ministry uses separate codes when these fields are simply missing on hospital diagnostic services billed as in-patient (service location indicator HIP): V65 (no master number), V66 (no admission date) and V67 (neither).

Common causes

The admission date was left blank or is in the wrong format
The master number is wrong, or isn't valid on the service date
An in-patient service was billed without the hospital and admission details

How to fix it

Get the hospital's master number and the patient's admission date from the hospital record for this stay.
Enter both on the claim and check that the admission date is the one for this stay.
Resubmit the corrected claim 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

You can't confirm the admission date or master number. Sending a guess will reject again.

How APEX handles it

APEX reads your error reports and remittance advice from MCEDT and, for many claims rejected with this code, works out the fix for you to approve before it is resubmitted. See how APEX works · Pricing

Related codes: AH5, H8, HM, V18, V28, V65, V66, V67