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Practice Management & Allied Staff News & Materials

Coding Modifiers

January 17th, 2012

Modifiers are additional two-digit numbers added to a code to indicate special circumstances have altered the service or procedure, but not changed its definition or code. After the procedure has been coded, attention should turn to the possible need for modifiers to make the carrier aware of services or procedures performed that may vary from the basic code because of a specific circumstance (e.g., reporting of bilateral procedures, indicating a procedure was performed more than once, reporting the assistant surgeon for the reported procedure, reporting that only a portion of the procedure was rendered, etc.). It may be necessary to support the modified code by submitting additional documentation to clarify the modification being reported.

Modifiers may be added to any CPT code. A general description of modifiers appears in the front of the full CPT book as part of the "Introduction" section. A complete listing of modifiers is contained in Appendix A (before the "Index" in the rear of the book). A complete list of HCPCS Level II Modifiers can be located in the introduction of the "2011 HCPCS Medicare Level II Expert." AAOMS recommends purchasing a new HCPCS book, CPT book and CDT book once they are updated every year. Some third party payers, such as Medicare, require the use of Modifiers in some circumstances, and others do not recognize the use of Modifiers by dentists. If a practice or office is unsure of their third party payer's stance on Modifiers, they should communicate with the payer to gain a clear understanding of their coding guidelines.

OMS specialties do not regularly use all CPT modifiers and HCPCS Level II modifiers. The following are the most common CPT modifiers and HCPCS Level II modifiers used in the OMS fields and settings.

*For a complete list of modifiers please see the Appendix located in the CPT and HCPCS Level II manuals.

CPT Modifiers


HCPCS Level II Modifiers



Significant separately identifiable E&M service by the same physician on the same day of the procedure or other service


Waiver of liability statement issued as required by payer policy, individual case


Professional component


"Opt out" physician or practitioner emergency or urgent service.


Anesthesia by surgeon


Notice of liability issued, voluntary under payer policy


Reduced services


Item or service statutorily excluded, does not meet the definition of any Medicare benefit or, for non-Medicare insurers, is not a contract benefit


Decision for surgery


Item or service expected to be denied as not reasonable and necessary


Staged or related procedure or service by the same physician during the postoperative period


CRNA service: with medical direction by a physician


Distinct Procedural Services


Medical direction of one certified registered nurse anesthetist (CFNA) by an anesthesiologist


Two surgeons


Left side/ Right side


Unplanned return to the operating/procedure room by the same physician or other qualified health care professional following initial procedure for a related procedure.


Technical Component


Unrelated procedure or service by the same physician during the postoperative period.




Assistant surgeon



Utilization and understanding of modifiers is essential to proper coding and reimbursement. Detailed instruction on the use of modifiers is provided in the AAOMS Coding Workshop series. Additional information on the AAOMS Coding Workshops may be found at

CPT only © 2011 American Medical Association
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