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G421
G421 – Subconjunctival or sub-Tenons capsule injection
OHIP Diagnostic & Therapeutic Procedures Code — DIAGNOSTIC AND THERAPEUTIC PROCEDURES · Schedule of Benefits
When to Use
- Use G421 for the administration of subconjunctival antibiotics or steroids to treat localized ocular inflammation or post-operative infection.
- Use G421 when performing a sub-Tenon's injection of anesthetic or corticosteroid for ocular surgery or management of chronic uveitis.
Common Pitfalls
- Failing to apply the 50% bilateral premium when injecting both eyes during the same encounter, which leads to underpayment.
- Billing G421 in conjunction with a minor procedure code that already includes the injection as a component of the global fee, resulting in a rejection for duplicate billing.
- Attempting to bill an office visit code (A007) on the same day as G421 without documenting a separate, medically necessary assessment unrelated to the injection procedure.
Billing Tips
- Ensure the claim includes the bilateral indicator if performing the procedure on both eyes to trigger the 50% additional benefit correctly.
- If the injection is performed during an emergency visit, append the appropriate Special Visit Premium from Tables I-X to maximize the claim value.
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