L841 – Enzyme histochemistry and interpretation
OHIP Dermatology Code — DIAGNOSTIC AND THERAPEUTIC PROCEDURES · Schedule of Benefits
This service covers the technical performance and professional interpretation of an enzyme histochemistry stain on a tissue specimen. The fee is applicable for each distinct enzyme analyzed. As per general requirements outlined in the Schedule (), this service must be medically necessary and documented in the patient's medical record. This service is not delegable to a non-physician (, ).
When to Use
- Use L841 when performing specific enzyme histochemistry stains, such as ATPase or NADH, on muscle biopsy samples to assist in the diagnosis of myopathies.
- Apply this code when analyzing distinct enzyme activity in tissue sections that are not covered under general histology codes like L834 or L835.
Common Pitfalls
- Billing L841 for routine H&E staining or standard immunohistochemistry, which are covered under different laboratory fee schedule categories.
- Submitting a single claim for multiple enzyme stains; each distinct enzyme analyzed requires a separate line item for L841 to ensure correct payment per enzyme.
- Failing to maintain the required physician-level interpretation documentation, as this service is strictly non-delegable under GP62 and GP63.
Billing Tips
- Ensure the pathology report clearly identifies each specific enzyme stain performed to justify the quantity of L841 units claimed.
Effective: April 1, 2026
J. Diagnostic and Therapeutic Procedures
DIAGNOSTIC AND THERAPEUTIC PROCEDURES
Laboratory
Diagnostic and Therapeutic Procedures
All insured services must be documented in appropriate records to establish that: an insured service was provided, the service for which the account is submitted is the service that was rendered, and the service was medically necessary ().
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