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Billing code

A623A — Medical Specific Assessment

Clinical immunology specialist assessment

Bill A623 for a clinical immunologist's full history of the presenting complaint and detailed exam of the affected systems, outside the patient's home.

Watch for: One per patient per physician per 12 months, unless the diagnosis is clearly unrelated; for hospital in-patients bill C623 instead.

Code

A623A

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

Clinical immunology medical specific assessment: full history of the complaint and detailed exam of the affected systems. One per patient per 12 months.

What it covers

A623 is the medical specific assessment in the Clinical Immunology (62) listing (A83). It is a specialist service, rendered somewhere other than the patient's home, with 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 (GP23).

The Clinical Immunology listing refers to the Internal Medicine section for services it doesn't list (A83).

Billing rules

• One per patient per physician per 12 months; two if the patient returns with a clearly different, unrelated diagnosis, or if at least 90 days have passed and the second is a hospital admission assessment. Extra ones pay as a lesser assessment (GP23).
• A623 and complex medical specific re-assessments (A621) combined are limited to 4 per patient per physician per 12 months (GP23-GP24).
• Not payable in the patient's home (GP23).
• In hospital in-patients, bill C623 (A84).
• No other Consultations and Visits service is payable for the same patient on the same day as A620 (initiation of food allergy immunotherapy) or K621 (FAIT support) (A83, A84).
• Can be billed by video or telephone as comprehensive virtual care when an existing patient-physician relationship exists, with K300A or K301A; telephone pays 85% (AJ1, A66, A70).

Often billed with

• E078 chronic disease assessment premium (+50%) in the office or a hospital out-patient clinic (not the ED), for an established chronic disease with a GP26 diagnostic code on the claim (A83, GP25-GP26).
• G209 (technical) and G197 (professional) skin tests, billed per test, each to a maximum of 50 per year (J5).
• G208 provocation testing for foods, food additives and medications, per hour or major part, to a maximum of 5 sessions per 12 months (J4).
• K301A when the assessment is done by telephone (A70).

Common rejections

• A4D: A623 is in the Clinical Immunology (62) listing, and specialists bill consultations and visits from their own specialty's listing (GP9). A claim under another registered specialty rejects; bill that specialty's code instead.
• EQ2: The specialty code on the claim wasn't registered and active for the physician on the service date. Correct it, or update the registration, then resubmit.
• EH2: The health card version code on the claim doesn't match OHIP's record, often because the patient has a newer card; get the current version code and resubmit.

Related codes: A624, A621, A628, A625, E078, C623

Source: Schedule of Benefits (July 1, 2026), Consultations and Visits, Clinical Immunology (62), pages A83-A84; General Preamble GP23 (medical specific assessment)

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