J304 – Volume versus Flow Study
OHIP Cardio-Thoracic Surgery Code — PULMONARY FUNCTION STUDIES · Schedule of Benefits
A Volume versus Flow Study from which an expiratory limb, and an inspiratory limb if indicated, are generated. A flow volume loop may include derivation of , VC, , . This service has a technical component (T) and a professional component (P).
When to Use
- Use J304 when performing a complete flow-volume loop to assess obstructive or restrictive lung disease, provided the study includes both expiratory and inspiratory limbs.
- Select J304 over J301 when the clinical requirement necessitates the visualization of the inspiratory limb to identify upper airway obstruction or variable extrathoracic obstruction.
Common Pitfalls
- Billing J304 on the same day as J301 or J324 will trigger an automatic rejection as these are mutually exclusive diagnostic procedures.
- Failure to include a signed, independent physician interpretation—relying solely on automated computer-generated reports—is a frequent cause of audit recovery.
- Submitting claims without ensuring the permanent record contains the mandatory 5mm/L/s flow and 10mm/L volume scaling on the tracings will result in non-compliance.
Billing Tips
- Ensure the technical component claim reflects the 94.68% adjustment if the service is performed within a hospital setting to avoid over-billing errors.
- Always document the 'best of three' maneuver results in the patient chart to satisfy the specific technical documentation requirement for this code.
Effective: April 1, 2025
H. Pulmonary Function Studies
PULMONARY FUNCTION STUDIES
Diagnostic
Pulmonary Function Studies, Diagnostic and Therapeutic Procedures
Must represent the best of three recorded test results or the study is not eligible for payment.
A permanent record that includes a written interpretation by the physician.
The permanent record includes constituent graph(s), tracing(s) and measurements with a scale on the tracing or graph of: - at least 5 mm per litre per second for flow; and - 10 mm per litre for volume.
The physician claiming the professional component must be able to demonstrate appropriate training in pulmonary function testing interpretation.
The physician submitting a claim for the technical component is responsible for the complete quality assurance process and must maintain documentation describing this process.
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