G804 – Hyperbaric oxygen therapy - physician in unit but not in chamber - first 1/4 hour
OHIP Diagnostic & Therapeutic Procedures Code — DIAGNOSTIC AND THERAPEUTIC PROCEDURES · Schedule of Benefits
Hyperbaric Oxygen Therapy (HBOT) is the service rendered when a physician administers and supervises HBOT. The specific elements of HBOT are those of an assessment, including ongoing monitoring of the patient's condition and intervening as appropriate. G804 is payable for the first 1/4 hour of a session per patient, where the physician is supervising from within the hyperbaric unit but is not inside the chamber with the patient(s). Time is calculated based on the period of physician supervision while each patient receives HBOT. See G805 for subsequent time.
When to Use
- Use G804 for the initial 15-minute block of supervision when the physician is present in the hyperbaric unit but outside the chamber during a standard treatment session.
- Use G804 when managing patients with approved indications like decompression sickness or carbon monoxide poisoning where the physician provides continuous oversight from the unit control area.
Common Pitfalls
- Billing G804 for the entire duration of the session instead of using G805 for all subsequent 15-minute increments.
- Failing to subtract time from the total G804/G805 claim if the HBOT session was interrupted to perform a separate, billable procedure on the patient.
- Submitting claims for ISSHL or AVN without documented evidence of the required specialist confirmation or diagnostic imaging staging, which leads to automatic audit recovery.
Billing Tips
- Ensure the medical record explicitly states the exact start and stop times for the physician's supervision period to justify the number of G804 and G805 units claimed.
- When treating multiple patients simultaneously, track and bill the supervision time per patient individually rather than billing a single block for the entire group.
Effective: April 1, 2025
J. Diagnostic and Therapeutic Procedures
DIAGNOSTIC AND THERAPEUTIC PROCEDURES
Procedure
Diagnostic and Therapeutic Procedures
The service is eligible for payment only if the start and stop times of the service are recorded in each patient's permanent medical record.
HBOT is insured only for the treatment of those internationally recognized indications approved by the ministry.
HBOT is only eligible for payment for idiopathic sudden sensorineural hearing loss (ISSHL) when the following conditions are met: - a. The patient is treated concurrently with corticosteroid unless corticosteroids are contraindicated; - b. The treatment is initiated within 30 days of a diagnosis of ISSHL; and - c. The diagnosis of ISSHL is made or confirmed by an Otolaryngologist prior to the initiation of treatment.
HBOT is only eligible for payment for avascular necrosis (AVN) of bone following diagnostic imaging confirmation of symptomatic early to mid-stage AVN, e.g. Ficat stage I, II, or III or equivalent.
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