What is OHIP billing code S321?

S321 is "Laparotomy for acute trauma", an OHIP Urology code from the Ontario Schedule of Benefits (Physician Services).

How much does S321 pay?

The current OHIP fee for S321 is $671.65, effective 2026-04-01, per the Ontario Schedule of Benefits.

How do I bill S321 to OHIP?

S321 is submitted through OHIP's MCEDT claims system, either directly or via billing software. SnapBill validates S321 claims against the Schedule of Benefits rules before submission.

What codes are related to S321?

Codes related to S321 in the Schedule of Benefits include E733, E734, E735, E736, E739, E723, E693, E694.

All codes

S321

S321 – Laparotomy for acute trauma

OHIP Urology Code — DIGESTIVE SYSTEM SURGICAL PROCEDURES · Schedule of Benefits

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Laparotomy for acute trauma is a major surgical procedure involving an incision into the abdominal cavity to diagnose and treat injuries resulting from acute trauma. This service includes all common and specific elements of a surgical procedure as defined in the Schedule of Benefits.

When to Use

Use S321 for an emergent exploratory laparotomy performed specifically to diagnose and manage intra-abdominal injuries following blunt or penetrating trauma.
Use S321 as the base procedure code when performing damage control surgery for a hemodynamically unstable trauma patient.

Common Pitfalls

Do not bill S321 for elective abdominal surgeries or non-trauma related procedures, as this will lead to automatic rejection or recovery during audit.
Failing to document the Injury Severity Score (ISS) in the chart will result in the denial of the E420 trauma premium, even if the patient meets clinical criteria.
Billing E733 (single repair) and E734 (multiple/resection) simultaneously is a common error; these codes are mutually exclusive based on the extent of the intestinal injury.

Billing Tips

Always verify if the procedure qualifies for the E420 trauma premium by ensuring the ISS is >15 for adults or >12 for pediatrics and is clearly noted in the operative report.
When performing complex multi-organ trauma, ensure all applicable add-on codes (e.g., E735 for splenectomy or E736 for liver repair) are submitted on the same claim as S321 to ensure proper reimbursement for the full scope of the procedure.

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Provider Fee$671.65

Surgical Assistant Fee$77.46

Anaesthetist Fee$95.76

Non-Anaesthetist Fee$95.76

Effective: April 1, 2026

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