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Billing code

J311C — Functional Residual Capacity - By Gas Dilution Method

Lung volume by gas dilution

Bill J311 for functional residual capacity (lung volume) measured by gas dilution.

Watch for: Not billable the same day for the same patient as J307, the plethysmography version of the same measurement.

Code

J311C

Description

Functional Residual Capacity - By Gas Dilution Method

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

Functional residual capacity (lung volume) measured by gas dilution, with technical and professional components.

What it covers

J311 measures functional residual capacity by the gas dilution method (H5).

The professional component covers supervision, quality control, any monitoring and the interpretation; the technical component covers performing the test and sending a signed written report to the referring provider (H1).

Billing rules

• Not billable the same day for the same patient as J307, FRC by body plethysmography (H5).
• Technical component (H, suffix B) is paid only at a hospital or a hospital's approved off-site premises; outside hospital only the professional component (P, suffix C) is billable (H1, H3).
• Each test with its own code is specific and must be ordered individually (H3).
• The interpretation must be done personally by the physician who claims the professional component; supervision and monitoring may be delegated to another physician (H1).
• Not payable for routine pre-operative screening before non-thoracic surgery, unless needed for respiratory diagnosis, anaesthetic decisions or optimizing respiratory disease before surgery (H3).

Often billed with

• J310 diffusing capacity and J304 flow volume loop, each ordered individually (H3–H5).

Common rejections

• ADH: OHIP's message is 'Cannot be billed together': J311 and J307 were both billed for the same patient the same day (H5).

Related codes: J307, J310, J304, J301

Source: Schedule of Benefits (July 1, 2026), Pulmonary Function Studies, Pulmonary Function Studies, page H5. Preamble H1–H3.

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