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G458
G458 – Single fibre electromyography
OHIP Diagnostic & Therapeutic Procedures Code — DIAGNOSTIC AND THERAPEUTIC PROCEDURES · Schedule of Benefits
Single fibre electromyography. This service includes all the common elements of an insured service as defined in the Schedule of Benefits (see -).
When to Use
- Use G458 specifically for the diagnostic assessment of neuromuscular junction disorders, such as myasthenia gravis, when standard repetitive nerve stimulation is inconclusive.
- Select G458 when performing specialized jitter analysis on single muscle fibers to confirm a diagnosis of a presynaptic or postsynaptic neuromuscular transmission defect.
Common Pitfalls
- Billing G458 in conjunction with E409 or E410 will result in a rejection because single fibre EMG is not classified as a major invasive procedure eligible for after-hours premiums.
- Attempting to claim age-based premiums (e.g., K035) with G458 is a common error that leads to automatic claim adjustment or rejection by the Ministry.
Billing Tips
- Ensure the referral source is clearly documented in the patient record, as G458 strictly requires a valid referral from a physician, nurse practitioner, or oral maxillofacial surgeon.
Provider Fee$275.00
Effective: April 1, 2026
Since Apr 2004, this fee has increased 43.5% vs 58.5% CPI inflation
Category
J. Diagnostic and Therapeutic Procedures
Subcategory
DIAGNOSTIC AND THERAPEUTIC PROCEDURES
Service Type
Procedure
Code Classes
Diagnostic and Therapeutic Procedures
Referral RequiredFrom: Physician, NursePractitioner, OralMaxillofacialSurgeon
All insured services must be documented in an appropriate record that establishes: 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 (see ).
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