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Billing code

A413A — Medical Specific Assessment

Gastroenterology specialist assessment

Bill A413 for a gastroenterologist's full history of the presenting complaint and detailed exam of the affected parts or systems, outside the patient's home.

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

Code

A413A

Description

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

A gastroenterologist's full assessment of the presenting complaint with a detailed exam of the affected parts or systems, outside the home.

What it covers

A medical specific assessment is rendered by a specialist outside the patient's home. It needs a full history of the presenting complaint and a detailed exam of the affected part(s), region(s) or system(s) needed to diagnose, exclude disease or assess function (GP23).

It is a specialist assessment level (GP23), billed from the Gastroenterology (41) listing (A104).

Billing rules

• Medical specific assessments: one per patient per physician per 12 months, or two if a clearly different, unrelated diagnosis is made or the second is a hospital admission assessment at least 90 days after the last. Extras pay a lesser fee (GP23).
• Medical specific assessments and complex medical specific re-assessments combined are limited to 4 per patient per physician per 12 months (GP23–GP24).
• Add E098 (+28%) for patients with established Crohn's disease, ulcerative colitis, malnutrition, celiac disease or chronic liver cirrhosis, seen in the office or a hospital out-patient clinic (not ED) (A104–A105).
• If a major pre-operative visit was done by any physician in the prior 12 months, A120 is the only assessment payable on the day of a colonoscopy (A104).
• Before a Z-code procedure the same day, only a partial assessment (A418) is payable if your major pre-operative visit was in the prior 12 months (SP4).
• Virtual care by video or phone with an existing patient-physician relationship; add K300A or K301A. Phone pays 85% (Appendix J AJ1, A66, A70).

Often billed with

• E098 gastroenterology chronic disease assessment premium (A104).
• K300A or K301A modality indicator for virtual care (A70).

Common rejections

• AT3: Usually means it was billed as virtual care and OHIP found no existing patient-physician relationship, such as an in-person service with you in the past 24 months or a video consultation in that time (A66).

Related codes: A414, A411, A418, A415, E098, C413

Source: Schedule of Benefits (July 1, 2026), Consultations and Visits, Gastroenterology (41), page A104.

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