G351 – Esophageal reflux monitoring study
OHIP Diagnostic & Therapeutic Procedures Code — DIAGNOSTIC AND THERAPEUTIC PROCEDURES · Schedule of Benefits
G351 is an oesophageal pH study conducted to evaluate for reflux. The procedure includes the installation of acid and requires 24-hour monitoring. As per the General Preamble, this service must be medically necessary and appropriately documented in the patient's medical record ().
When to Use
- Use G351 when performing a formal 24-hour ambulatory esophageal pH monitoring study to quantify acid reflux episodes in patients with refractory GERD symptoms.
- Select G351 for diagnostic confirmation of gastroesophageal reflux disease when standard PPI therapy has failed and objective evidence of acid exposure is required.
Common Pitfalls
- Billing G351 in conjunction with G350 (esophageal manometry) on the same day may trigger a manual review or rejection if the documentation does not clearly distinguish the two distinct diagnostic procedures.
- Failure to include the mandatory physician referral on the claim will result in an automatic rejection, as G351 is a diagnostic procedure requiring a formal request from another provider.
Billing Tips
- Ensure the claim reflects the 24-hour duration requirement; billing G351 for shorter, non-standard monitoring periods is a common cause of audit adjustments.
Effective: April 1, 2026
J. Diagnostic and Therapeutic Procedures
DIAGNOSTIC AND THERAPEUTIC PROCEDURES
Diagnostic
Diagnostic and Therapeutic Procedures
As per , all insured services must be documented in appropriate records. The record must establish that: 1. an insured service was provided; 2. the service for which the account is submitted is the service that was rendered; and 3. the service was medically necessary.
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