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Billing code

G538A — Other Immunizing Agents

Other vaccine

Bill G538 for an immunization with a vaccine that has no specific OHIP code; add G700 when it is the only reason for the visit.

Watch for: Use the vaccine's own code when one exists, such as G590 for influenza or G593 for COVID-19.

Code

G538A

Description

Other Immunizing Agents

FHO+ basket

Covered by the FHO+ base rate payment for enrolled patients, and shadow billed at 30% (50% for Schedule 2B procedures).

Effective date

Apr 1, 2026

Termination date

No end date

Explanation

Updated October 26, 2026

Immunization with a vaccine that has no specific OHIP code of its own. Add G700 when the shot is the only reason for the visit.

What it covers

G538 is the immunization code for 'other immunizing agents not listed above' (J54). Use it only when the vaccine isn't one of the specifically listed agents: DTaP-IPV (G840), DTaP-IPV-Hib (G841), hepatitis B (G842), HPV (G843), Men-C (G844), MMR (G845), pneumococcal conjugate (G846), Tdap (G847), varicella (G848), RSV (G849), influenza (G590) or COVID-19 (G593).

Billing rules

• Marked (+): when the immunization is the sole reason for the visit, add G700, once per patient per day however many vaccines or (+) procedures are given (J3, J54).
• G700 is not payable in hospital, and is paid at 15% of its fee for patients enrolled to a capitation-based group (J3).
• May be delegated to trained office staff, even when you aren't on site, for your own patient; the chart must name who gave it (GP62–GP63).
• Payable on the same day as a counselling service by the same physician (GP58).
• The Schedule notes an immunization may be uninsured in some circumstances and refers to section 24 of Regulation 552 under the Health Insurance Act (J54, AA1).
• FHO: a Schedule 2B core service, so for enrolled patients shadow billing is 50% of the fee (Agreement p.59 §4.3–4.4, p.88).

Often billed with

• G700 when vaccines (alone or with other (+) procedures) are the only reason for the visit (J3, J54).
• An assessment such as A007 (intermediate assessment or well baby care) when the vaccine is given at a regular visit; G700 isn't added then, because the vaccine isn't the sole reason (A4, J3).

Common rejections

• VJ7: OHIP received the claim more than three months after the service date, so it was rejected as stale-dated (GP9).
• 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.
• V23: OHIP questioned the number of services on the line; check the count and that the code carries the A suffix for your own service.
• VH9: The health number on the claim isn't registered with the Ministry; check it against the patient's card and resubmit.
• EH4: OHIP's record shows the patient's coverage ended before the service date; confirm the health number and service date, then the patient's coverage.

Related codes: G700, G590, G593, G840, G841, G842, G843, G844, G845, G846, G847, G848, G849

Source: Schedule of Benefits (July 1, 2026), Diagnostic and Therapeutic Procedures, Injections or Infusions — Immunization, page J54

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