A modifier provides the means by which the reporting physician or provider can indicate that a service or procedure that has been performed has been altered by some specific circumstance but not changed in its definition or code.
Level I modifiers are codes and descriptors copyrighted by the American Medical Association's current procedural terminology (CPT).
Level II modifiers are codes and descriptors approved and maintained jointly by the alpha-numeric editorial panel (consisting of CMS, the Health Insurance Association of America, and the Blue Cross and Blue Shield Association).
| Modifier | Description | Effective | |
|---|---|---|---|
| X4 | Episodic/focused services: for reporting services by clinicians who provide focused care on particular types of treatment limited to a defined period and circumstance; the patient has a problem, acute or chronic, that will be treated with surgery, radiation, or some other type of generally time-limited intervention; reporting clinician service examples include but are not limited to, the orthopedic surgeon performing a knee replacement and seeing the patient through the postoperative period | Jan 01, 2018 | |
| X5 | Diagnostic services requested by another clinician: for reporting services by a clinician who furnishes care to the patient only as requested by another clinician or subsequent and related services requested by another clinician; this modifier is reported for patient relationships that may not be adequately captured by the above alternative categories; reporting clinician service examples include but are not limited to, the radiologist's interpretation of an imaging study requested by another clinician | Jan 01, 2018 | |
| XE | Separate encounter, a service that is distinct because it occurred during a separate encounter | Jan 01, 2015 | |
| XP | Separate practitioner, a service that is distinct because it was performed by a different practitioner | Jan 01, 2015 | |
| XS | Separate structure, a service that is distinct because it was performed on a separate organ/structure | Jan 01, 2015 | |
| XU | Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service | Jan 01, 2015 | |
| ZA | Novartis/sandoz | Apr 01, 2018 | |
| ZB | Pfizer/hospira | Apr 01, 2018 | |
| ZC | Merck/samsung bioepis | Apr 01, 2018 |