HCPCS Modifiers List

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).

Modifiers may be used to indicate to the recipient of a report that:

A service or procedure has both a professional and technical component.
A service or procedure was performed by more than one physician and/or in more than one location.
A service or procedure has been increased or reduced.
Only part of a service was performed.
An adjunctive service was performed.
A bilateral procedure was performed.
A service or procedure was provided more than once.
Unusual events occurred.

Modifier	Description	Effective
A1	Dressing for one wound	Jul 01, 2002
A2	Dressing for two wounds	Jul 01, 2002
A3	Dressing for three wounds	Jul 01, 2002
A4	Dressing for four wounds	Jul 01, 2002
A5	Dressing for five wounds	Jul 01, 2002
A6	Dressing for six wounds	Jul 01, 2002
A7	Dressing for seven wounds	Jul 01, 2002
A8	Dressing for eight wounds	Jul 01, 2002
A9	Dressing for nine or more wounds	Jul 01, 2002
AA	Anesthesia services performed personally by anesthesiologist	Jan 01, 2001
AB	Audiology service furnished personally by an audiologist without a physician/npp order for non-acute hearing assessment unrelated to disequilibrium, or hearing aids, or examinations for the purpose of prescribing, fitting, or changing hearing aids; service may be performed once every 12 months, per beneficiary	Jan 01, 2023
AD	Medical supervision by a physician: more than four concurrent anesthesia procedures	Jan 01, 2001
AE	Registered dietician	Jan 01, 2005
AF	Specialty physician	Jan 01, 2005
AG	Primary physician	Jan 01, 2005
AH	Clinical psychologist	Jan 01, 1997
AI	Principal physician of record	Jan 01, 2010
AJ	Clinical social worker	Jan 01, 1997
AK	Non participating physician	Jan 01, 2005
AM	Physician, team member service	Jan 01, 1997
AO	Alternate payment method declined by provider of service	Oct 01, 2013
AP	Determination of refractive state was not performed in the course of diagnostic ophthalmological examination	Jan 01, 1997
AQ	Physician providing a service in an unlisted health professional shortage area (hpsa)	Jan 01, 2006
AR	Physician provider services in a physician scarcity area	Jan 01, 2005
AS	Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery	Jan 01, 1999