Z491 – Follow up of incomplete polyp resection
OHIP Psychiatric Code — DIGESTIVE SYSTEM SURGICAL PROCEDURES · Schedule of Benefits
A colonoscopy for diagnosis or ongoing management, specifically for the follow-up of an incomplete polyp resection. Payment for this service is conditional on the following: - It is for sessile polyps that were only partially removed, or for adenomatous polyps that were removed piecemeal or contained high grade dysplasia. - It is performed within six months of the initial colonoscopy; claims for services performed after six months are not eligible for payment.
When to Use
- Use for the follow-up colonoscopy of a sessile polyp that was only partially resected during a previous procedure.
- Use for the follow-up colonoscopy of an adenomatous polyp that was removed via piecemeal technique.
- Use for the follow-up colonoscopy of a polyp that was confirmed to contain high-grade dysplasia on the initial pathology report.
Common Pitfalls
- Claims submitted for a procedure performed more than six months after the initial colonoscopy will be rejected.
- Billing Z491 in conjunction with any other Z-prefix colonoscopy codes (Z492-Z499, Z555) on the same day will result in a rejection.
- Attempting to bill anaesthesia time units or extra units with E032C is non-compliant; only the 4 basic units are payable.
Billing Tips
- Ensure the procedure date is strictly within the six-month window from the initial resection to avoid automatic rejection.
- When billing anaesthesia, use E032C exclusively and omit any additional time-based or extra unit modifiers to ensure the claim processes correctly.
Effective: April 1, 2025
S. Digestive System Surgical Procedures
DIGESTIVE SYSTEM SURGICAL PROCEDURES
Surgical
Digestive System Surgical Procedures
Only one of Z491, Z492, Z493, Z494, Z495, Z496, Z497, Z498, Z499 or Z555 is eligible for payment per patient per day.
Time units and anaesthesia extra units listed on are not eligible for payment with anaesthesia services for Z491C, Z492C, Z493C, Z494C, Z495C, Z496C, Z497C, Z498C, Z499C or Z555C.
E003C is not payable for anaesthesia services rendered for Z491, Z492, Z493, Z494, Z495, Z496, Z497, Z498, Z499 or Z555.
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