Two-digit modifiers for CPT and HCPCS codes indicate that a service or procedure that has been performed has been altered by some specific circumstances, but not changed in its definition. Examples include the following:
- Modifier 22 - Unusual Service: The service provided is greater than that usually required for the listed procedure. For example, a speech and language evaluation (CPT 92506) that requires twice the amount of time as "typical."
- Modifier RT and LT - Side of body: Indicates service performed on the right or left side of the body.
- Modifier 76 and 77 - Repeat Procedure: Modifier 76 indicates that the procedure was repeated by the same physician in the same day. Modifier 77 indicates that the procedure was repeated by another physician.
More than one modifier may be used for an individual HCPCS/CPT code. When billing HCPCS/CPT codes with more than one modifier, the functional modifier is supposed to be placed in the first modifier field. Informational modifiers should be placed in the second modifier field. For example, if a physician billed a CPT code with both the modifier 22 for unusual services and the modifier LT to indicate the procedure was performed on the left side of the body, the 22 would be placed in the first modifier field and the LT would be placed in the second modifier field.
During HCUP processing, modifiers are validated. Invalid modifiers are set to "i".