General Surgery Coding Alert

Find out how and why to use this modifier the right way every time.

Modifier 59 (Distinct procedural service) just turned 30, but federal agencies, including the Centers for Medicare & Medicaid Services (CMS) and the Office of Inspector General (OIG), and payers have described it as being overused and misused.

Find out everything you need to know to use modifier 59 correctly.

Understand the Background

Modifier 59 was created to provide a way for coders to report multiple services that otherwise might be bundled, explained Lori Cox, MBA, CPC, CPMA, CPC-I, CEMC, CGSC, CHONC, in her presentation “Modifier 59: The Other Misused Modifier” for AAPC’s HEALTHCON 2025.

According to the Medicare Learning Network (MLN), modifier 59 is “used to identify procedures/services, other than [evaluation and management] E/M services, that are not normally reported together, but are appropriate under the circumstances.”

Documentation is crucial for supporting the use of modifier 59, and MLN gives examples of situations where the modifier might be appropriate: a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury “not ordinarily encountered or performed on the same day by the same individual.”

CMS tried to mitigate the use of modifier 59 by creating the X{EPSU} modifiers, Cox explained. These modifiers are:

• XE (Separate encounter, a service that is distinct because it occurred during a separate encounter)
• XP (Separate practitioner, a service that is distinct because it was performed by a different practitioner)
• XS (Separate structure, a service that is distinct because it was performed on a separate organ/structure)
• XU (Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service)

MLN notes that these modifiers are more specific than modifier 59 and should be used instead of modifier 59 whenever possible.

“These modifiers are mainly used for Medicare patients, if they apply, but I have seen some other payers allow it as well,” Cox said. “If one of these X modifiers applies, I would try to use that. Try it with your payers and see if they accept it or not.”

When coders think of modifier 59, they often think about the National Correct Coding Initiative (NCCI). “NCCI edits are the main reason why modifier 59 gets used or misused,” Cox said. She explained that when people put codes into a product like AAPC’s Codify, Codify tells the user whether they’re bundled, at which point the coder needs to decide whether to use modifier 59.

Consider These Examples

Example 1: A patient comes into a practice for a stress test scheduled in the morning. The test is performed and the patient is sent home. This service can be billed with 93015 (Cardiovascular stress test using maximal or submaximal treadmill or bicycle exercise, continuous electrocardiographic monitoring, and/or pharmacological stress; with supervision, interpretation and report). The patient returned in the afternoon of the same day complaining of chest pains, and a clinician performed an electrocardiogram (EKG).

“Now, an EKG cannot be billed with a stress test. If they’re done at the same time, they’re bundled, so we would only bill a stress test. But in this case, the patient comes back in the afternoon and gets an EKG, it’s a separate time of day,” she explained. In this situation, using a modifier shows that the EKG was performed as a separate and distinct service from the earlier stress test, even though they were performed on the same date. Coders could append modifier XE to the EKG encounter to show that it was a separate encounter.

Example 2: A provider performs a procedure to destroy lesions on the retina and choroid of the same eye, and the coder reports CPT^® codes 67210 (Destruction of localized lesion of retina (eg, macular edema, tumors), 1 or more sessions; photocoagulation) and 67220 (Destruction of localized lesion of choroid (eg, choroidal neovascularization); photocoagulation (eg, laser), 1 or more sessions).

When you run these two codes through Codify, you get an edit: You can’t just bill these two procedures together, Cox said, unless you have a reason. “When you run it through the edits, you see that the 67210 is bundled with the 67220; we can override it with a modifier if the guidelines meet it. So how do we know if the guidelines meet it? You need to read the [operation] OP note.”

However, CMS says the retina and choroid are contiguous structures of the same organ; so, if you’re doing this procedure on the same eye, you would only bill one service.

“But CMS’ MLN Matters manual tells us that they give this as an example to use XS … so sometimes you have to take that with a grain of salt and realize that the whole point of it is that it’s supposed to be a separate structure,” Cox said.

“Code 67220 is a column 2 code for 67210, but you may use an NCCI-associated modifier to override the edit under appropriate circumstances. The NCCI edit rule: Mutually exclusive procedures,” Cox quoted.

Rachel Dorrell, MA, MS, CPC-A, CPPM, Development Editor, AAPC