What are the billing rules for C604A?

Limited to two per patient per physician per 12 months, except re-assessments for hospital admissions. Excess claims pay as a lesser assessment (GP23). An admission assessment counts as a re-assessment when the same physician assessed the patient for the same illness before admitting them (within 90 days of admission) (GP23, GP40). The congestive heart failure premium (E088) is not payable for in-patients (A79).

What is C604A often billed with?

E082 admission assessment by the MRP (+30%) when this service is your admission assessment as MRP; once per admission, not for transfers within the hospital (GP42). C101 ICU/CCU premium for each patient seen on a visit to the ICU or CCU, unless a critical care, ventilatory or comprehensive care team fee is claimed (GP103).

Why is C604A rejected?

AT2: OHIP's message is 'Must Include Video Modality': in-patient (C-prefix) virtual services are video only, so a phone claim (K301A) is refused (AJ2).

< Billing codes

Billing code

C604A — Medical Specific Re-assessment

Q: What is OHIP billing code C604A?

Medical specific re-assessment by a cardiologist for a hospital in-patient: full relevant history and exam of one or more systems.

Cardiology in-patient re-assessment

Bill when a cardiologist re-assesses a hospital in-patient with a full relevant history and exam of one or more systems.

Watch for: Limited to 2 per patient per physician in 12 months, except admission re-assessments; extras pay as a lesser assessment.

Provider	Specialist	Assistant	Anaesthetist	Non-anaesthetist
$0.00	$72.65	$0.00	$0.00	$0.00

Code: C604A
Description: Medical Specific Re-assessment
FHO+ basket: Not in the FHO+ base rate basket (Schedule 2 or 2B).
Effective date: Apr 1, 2026
Termination date: No end date

Explanation

Updated October 26, 2026

Medical specific re-assessment by a cardiologist for a hospital in-patient: full relevant history and exam of one or more systems.

What it covers

C604 is a medical specific re-assessment by a cardiologist for a non-emergency hospital in-patient (A80).

A medical specific re-assessment is a specialist service that needs a full, relevant history and physical exam of one or more systems (GP23).

Billing rules

Limited to two per patient per physician per 12 months, except re-assessments for hospital admissions. Excess claims pay as a lesser assessment (GP23).
An admission assessment counts as a re-assessment when the same physician assessed the patient for the same illness before admitting them (within 90 days of admission) (GP23, GP40).
The congestive heart failure premium (E088) is not payable for in-patients (A79).
Virtual care: video only, not phone (Appendix J, AJ2). For an in-patient, you must not be the MRP, the hospital must lack a local physician with the expertise (documented by the referrer), and the referrer must have seen the patient in person within 30 days (A69).
For emergency calls and other special visits to in-patients, bill the A-prefix General Listings with special visit premiums instead (A80, GP65–GP78).

Often billed with

E082 admission assessment by the MRP (+30%) when this service is your admission assessment as MRP; once per admission, not for transfers within the hospital (GP42).
C101 ICU/CCU premium for each patient seen on a visit to the ICU or CCU, unless a critical care, ventilatory or comprehensive care team fee is claimed (GP103).

Common rejections

AT2: OHIP's message is 'Must Include Video Modality': in-patient (C-prefix) virtual services are video only, so a phone claim (K301A) is refused (AJ2).

Related codes: A604, C603, C601, C602, C606

Source: Schedule of Benefits (July 1, 2026), Consultations and Visits, Cardiology (60), page A80; rules GP23, GP40.

APEX checks every paid claim against the Schedule of Benefits and flags codes billed below what the visit qualified for. See how APEX works · Pricing