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Billing code

C133A — Internal medicine in-patient medical specific assessment

Internal medicine in-patient specialist assessment

Bill C133 for an internist's full history and detailed exam of the affected systems for a hospital in-patient.

Watch for: One per patient per physician per 12 months, unless the diagnosis is clearly unrelated; extras pay a lesser fee.

Code

C133A

Description

Internal medicine in-patient medical specific 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

Full internal medicine specialist assessment of a hospital in-patient: complete history and detailed exam of the affected systems.

What it covers

C133 is the Internal Medicine (13) medical specific assessment for non-emergency hospital in-patients (A130). A medical specific assessment needs a full history of the presenting complaint and a detailed examination of the affected parts, regions or systems needed to make a diagnosis, exclude disease or assess function. It is done by a specialist, somewhere other than the patient's home (GP23).

Hospital in-patient (C-prefix) services follow GP40–GP48. For emergency calls and other special visits to in-patients, use the General Listings and special visit premiums instead (A130).

Billing rules

• Specialists bill from the Consultations and Visits listing for their own Royal College specialty on file with the Ministry, here Internal Medicine (13) (GP9).
• One per patient per physician per 12 months, or two if the patient returns with a clearly different, unrelated diagnosis or (at least 90 days after the last) the second is a hospital admission assessment. Extra ones pay a lesser fee (GP23).
• Medical specific assessments and complex medical specific re-assessments together are limited to 4 per patient per physician per 12 months; extras pay a lesser fee (GP23–GP24).
• As an admission assessment, it applies when you haven't assessed the patient for the same illness in the 90 days before admission (GP40).
• Video only (not phone), and for a hospital in-patient or LTC resident only if you are not the MRP, the facility has no physician with the needed expertise (documented by the referrer), and the referrer saw the patient in person within the past 30 days (AJ2, A69).

Common rejections

• AT2: OHIP describes this as 'Must include video modality': this code is video-only in Appendix J, so it can't be billed by phone with K301A (AJ2).

Related codes: C134, C131, C135, A133, C132

Source: Schedule of Benefits (July 1, 2026), Consultations and Visits, Internal Medicine (13), page A130. Assessment rules GP23–GP25.

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