Modifier Codes Overview

Modifiers should be used to identify circumstances that alter or enhance the description of a service or supply.

Level I (CPT) modifiers are two numeric digits (21-99). They are described in detail in the current CPT manual and are updated annually by the American Medical Association.

Level II (HCPCS/National) modifiers are two alphabetic or alpha-numeric characters (e.g., AA or E1). They are recognized nationally and are updated annually by the Centers for Medicare & Medicaid Services. Many of these modifiers have a specific or limited use, but a complete list is in the current HCPCS manual.

In general, modifiers are used to clarify a service or supply and should be selected from the most recent editions of the CPT or HCPCS coding manuals.

Some modifiers that may be used by therapeutically certified optometrists include:

• Surgical Bilateral Procedures
• Modifier Code 25 - Vision
• Modifier Code 22
• Site-Specific Surgical Modifiers

Revision History