A modifier may be used in CPT and/or HCPCS codes to indicate

According to the AHIMA CDIP Exam Preparation Guide, a modifier is a two-digit numeric or alphanumeric code that may be used in CPT and/or HCPCS codes to indicate that a service or procedure has been altered by some specific circumstance, but not changed in its definition or code1. One of the reasons to use a modifier is to indicate that a service or procedure was increased or reduced in comparison to the usual service or procedure2. For example, modifier 22 can be used to report increased procedural services that require substantially greater time, effort, or complexity than the typical service3. The other options are not correct because they do not reflect the purpose of using modifiers. A service or procedure performed in its entirety does not need a modifier, as it is assumed to be the standard service or procedure. A service or procedure resulting in expected outcomes does not affect the coding or reimbursement of the service or procedure. A service or procedure performed by one provider may need a modifier depending on the type of provider, the place of service, and the payer rules, but it is not a general reason to use a modifier. References:

CDIP Exam Preparation Guide - AHIMA

Modifiers: A Guide for Health Care Professionals - CMS

CPT® Modifiers: 22 Increased Procedural Services | AAPC