What are the billing rules for C131A?

You must report your findings, opinions or recommendations in writing to the patient's primary care physician, or it is paid as a lesser assessment (GP24). Limited to 4 per patient per physician per 12 months; excess is paid as a lesser assessment (GP24). Any combination of medical specific assessments and complex medical specific re-assessments is also limited to 4 per patient per physician per 12 months (GP23–GP24).

Why is C131A rejected?

AT2: Billed by telephone (K301A). This code is on Appendix J's video-only list, so it must be done by video and claimed with K300A (AJ2).

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Billing code

C131A — Internal medicine complex medical specific re-assessment – hospital in-patient

Q: What is OHIP billing code C131A?

Internal medicine re-assessment of an in-patient whose condition is complex, obscure or serious, with a written report to the primary care physician.

Complex internal medicine in-patient re-assessment

Bill C131 when an internist re-assesses an in-patient because the condition is complex, obscure or serious, with a written report.

Watch for: Report in writing to the primary care physician, or it pays as a lesser assessment; limit 4 per patient per 12 months.

Provider	Specialist	Assistant	Anaesthetist	Non-anaesthetist
$0.00	$83.40	$0.00	$0.00	$0.00

Code: C131A
Description: Internal medicine complex medical specific re-assessment – hospital in-patient
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

Internal medicine re-assessment of an in-patient whose condition is complex, obscure or serious, with a written report to the primary care physician.

What it covers

A complex medical specific re-assessment is a re-assessment because of the complexity, obscurity or seriousness of the patient's condition. It includes everything in a medical specific re-assessment (a full relevant history and exam of one or more systems) (GP23–GP24).

C131 is the non-emergency hospital in-patient version; the office version is A131 (A129–A130).

Billing rules

You must report your findings, opinions or recommendations in writing to the patient's primary care physician, or it is paid as a lesser assessment (GP24).
Limited to 4 per patient per physician per 12 months; excess is paid as a lesser assessment (GP24).
Any combination of medical specific assessments and complex medical specific re-assessments is also limited to 4 per patient per physician per 12 months (GP23–GP24).
Seeing patients in the ED or out-patient department while not on ED duty uses the A-prefix General Listings, not C-codes (A130, A137).
For emergency calls and other special visits to in-patients, bill the A-prefix General Listings with special visit premiums instead (A130, A137; GP65–GP78).
By video only, and for in-patients or LTC residents only when you are not the MRP, no local physician with the expertise is available (documented by the referrer), and the referrer saw the patient in person within the prior 30 days (AJ2, A69).

Common rejections

AT2: Billed by telephone (K301A). This code is on Appendix J's video-only list, so it must be done by video and claimed with K300A (AJ2).

Related codes: A131, C133, C134, C135, C132, C138

Source: Schedule of Benefits (July 1, 2026), Consultations and Visits, Internal Medicine (13), page A130; rules GP23–GP24.

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