New Surgical Coding Modifiers Replace Modifier -59

January 28, 2015

Over the summer CMS added four new modifiers that will require a much greater degree of specification when coding surgical procedures.

In the dog days of summer CMS released a transmittal that will dog the steps of surgical coders in 2015. CMS added four new HCPCS modifiers to be used in place of modifier -59 in some situations. The AMA develops CPT modifiers, which are two digit numerical modifiers found in the CPT book. CMS develops modifiers, which are two digit alphabetic or alpha-numeric modifiers. CPT modifiers may be used on CPT or HCPCS codes, and HCPCS modifiers may be used on CPT or HCPCS codes. Most private insurances except both types of codes and modifiers as valid submissions on a claim form.

These four new modifiers are referred to as the -X (EPSU) modifiers and are now a subset of modifier -59. The CPT definition of modifier -59 is Distinct Procedural Service. The complete description is below:

• XE - Separate Encounter, a service that is distinct because it occurred during a separate encounter.

• XS - Separate Structure, a service that is distinct because it was performed on a separate organ/structure.

• XP - Separate Practitioner, a service that is distinct because it was performed by a different practitioner.

• XU - Unusual Non-Overlapping Service, the use of the service that is distinct because it does not overlap usual components of the main service.

CMS will continue to recognize modifier -59 in some instances, but the transmittal states that it may "selectively require a more specific -X (EPSU) modifier for billing certain codes at high risk for incorrect billing." This means, that for some services a group may continue to report modifier -59 and be paid for the service. In other instances, the Medicare contractor will return the claim unpaid and ask for the more specific modifier. Although CMS states that it will initially accept either modifier -59 or the more selective -X (EPSU) modifier, it hopes for a quick migration to the use of these new modifiers.

Some instructions are very clear. CMS prefers specific HCPCS location modifiers over the use of modifier -59 whenever relevant. This includes RT for right and LT for left as well as a long list of location modifiers found in Appendix A of the CPT book and in the HCPCS book. These describe eyelids, digits, and some arteries, such as -E1 for the upper left eyelid or -T8 for the right foot, fourth digit. Also, if a more specific CPT modifier is available, use it in place of modifier -59 or the -X (EPSU) modifiers. Modifier -59 and these replacement modifiers remain the modifiers of last resort.

The -XE modifier, separate encounter, is straightforward. Use it on a second procedure that is normally bundled into a primary procedure that is performed during a different encounter.

The -XS modifier, separate structure, will be useful for skin procedures as well as other types of procedures. For example, use this modifier to indicate that a punch biopsy on a lesion of the face was distinct from the excision of a different, separate benign lesion on the face.

The -XP modifier, separate practitioner, tells Medicare that the second procedure being reported was performed by a different practitioner. Keep in mind that CMS considers physicians in a group practice of the same specialty to be one physician. Although CMS has not described how it will interpret that rule with the -XP modifier, it may be that a covering partner who takes a patient back to the operating room will not be reimbursed even with the use of the -XP modifier. Keep in mind that if a more specific modifier describes the service, such as modifier -76, -77 or -78, use it.

The -XU modifier is defined as an unusual non-overlapping service. Although CMS does not give examples in either the transmittal or the MLN Matters article, one payer's website suggests that this modifier could be used for a diagnostic procedure that is performed and resulted in the need for a therapeutic procedure later in the day.

This Pearls article may raise more questions than it answers. This is the strategy to adopt: stop, look, and listen. Stop and read the three resources that are listed below. Pay special attention to the examples in the modifier -59 article below. These are examples of coding combinations CMS believes are at high risk for incorrect modifier use. Look to your specialty society for specific examples of the use of these modifiers for the procedures that are performed in your practice. Listen to your payers as they describe whether they will accept or require these modifiers and listen to your practice's denial staff, and learn from the denials when to use the new modifiers.


MedLearn Matters 8863 "Specific Modifiers for Distinct Procedural Services"

CMS Transmittal 1422 8/15/14 "Specific Modifiers for Distinct Procedural Services"

Medicare's National Correct Coding Initiative Edits "Modifier 59 Article"

Betsy Nicoletti is the cofounder of She is the author of “A Field Guide to Physician Coding.” She believes all physicians can improve their compliance and increase their revenue through better coding. She may be reached at or 802 885 5641.