G850 – Colour vision detailed assessment - technical component
OHIP Diagnostic & Therapeutic Procedures Code — DIAGNOSTIC AND THERAPEUTIC PROCEDURES · Schedule of Benefits
Colour vision detailed assessment (not to be claimed for screening tests such as Ishihara, HRR and University, etc.) only where underlying pathology is present or suspected. Requires that the following services are rendered: one of the screening tests and at least two (2) of the following detailed tests: 100 Hue, D-15, Lathony New Colour Test or anomaloscope test. To be performed where underlying pathology is present or suspect. Not to be performed as a routine screening test.
When to Use
- Use G850 when investigating acquired dyschromatopsia in patients with suspected optic neuritis or toxic maculopathy, provided you have performed one screening test plus two advanced tests like the 100 Hue and D-15.
- Use G850 for detailed monitoring of progressive retinal diseases where standard screening tests like Ishihara are insufficient to document functional decline.
Common Pitfalls
- Claiming G850 for routine Ishihara or HRR screening will result in a rejection or audit recovery, as these are explicitly excluded by the Schedule of Benefits.
- Failing to document the specific results of two distinct advanced tests (e.g., 100 Hue and anomaloscope) alongside the initial screening test will lead to a claim reversal during a post-payment audit.
- Billing G850 in the absence of a documented underlying pathology, such as using it for simple congenital colour blindness diagnosis, is a non-compliant use of this diagnostic code.
Billing Tips
- Ensure your clinical notes explicitly list the two advanced tests performed to meet the mandatory threshold, as the Ministry requires this specific evidence for the technical component.
- If performing this service in a hospital setting, remember that the fee is automatically adjusted to 86.10% of the listed rate, so do not attempt to manually adjust the fee in your billing software.
Effective: April 1, 2026
J. Diagnostic and Therapeutic Procedures
DIAGNOSTIC AND THERAPEUTIC PROCEDURES
Diagnostic
Diagnostic and Therapeutic Procedures
The physician maintains documentation that describes the process by which the physician monitors quality assurance in accordance with professional standards.
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