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Billing code

J304C — Flow Volume Loop T

Flow volume loop

Bill J304 for a flow volume loop spirometry study; the repeat after a bronchodilator is J327.

Watch for: Not payable the same day as J301 or J324 for the same patient, and the result must be the best of three.

Code

J304C

Description

Flow Volume Loop T

FHO+ basket

Covered by the FHO+ base rate payment for enrolled patients, and shadow billed at 30% (50% for Schedule 2B procedures).

Effective date

Apr 1, 2026

Termination date

No end date

Explanation

Updated October 26, 2026

Flow volume loop: a volume-versus-flow spirometry study with an expiratory limb (and inspiratory limb if indicated). Repeat after bronchodilator is J327.

What it covers

J304 is a volume-versus-flow study that generates an expiratory limb, and an inspiratory limb if indicated. It may include derivation of FEV1, VC, V50 and V25 (H4). The repeat after a bronchodilator is J327.

Pulmonary function tests have a professional component (supervision, interpretation) and a technical component (performing the test, records, a signed written report to the referring provider) (H1–H2).

Billing rules

• Technical (T, suffix B) and professional (P, suffix C) components are claimed separately (H3).
• Unlike most pulmonary function tests, the technical component is payable in the office (H3). In hospital it is paid at 86.10% of the T fee, and never for in-patients or patients admitted to the same hospital within 24 hours for the same condition (GP11).
• Not payable with J301 or J324 for the same patient on the same day (H4).
• The result must be the best of three recorded tests, or the study is not eligible for payment (H4).
• Payable only with a permanent record that has a written physician interpretation and the graphs or tracings, scaled at least 5 mm per litre per second for flow and 10 mm per litre for volume (H4).
• The physician claiming the professional component must be able to show training in pulmonary function interpretation; computer-generated interpretation alone doesn't qualify (H4).
• Can be delegated to trained office staff, even with the physician off site, for your own patient, with chart documentation of who did it (GP62–GP63).
• FHO: J304C is an in-basket (Schedule 2) code (Agreement p.78).

Often billed with

• J327 when repeated after a bronchodilator (H4).

Common rejections

• ADH: J304 was billed the same day as J301 or J324 for the same patient; these cannot be billed together (H4).

Related codes: J327, J301, J324, J310, J307, J315

Source: Schedule of Benefits (July 1, 2026), Pulmonary Function Studies, Flow volume loop, page H4.

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