Blog Post

When Should I Use Modifier 59?

Confused about when and how to bill using the 59 modifier? This blog post breaks it all down in terms you can actually understand.

Brooke Andrus
5 min read
July 28, 2017
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In a PT’s paradise, the billing process wouldn’t exist. Therapists would simply provide treatment and receive payment accordingly, no explanation—or coding—required. In the real world, though, claims—and the codes and modifiers you submit with those claims—are your ticket to getting paid. And in many situations, one little modifier could have a big impact on your bottom line. Such is the case with modifier 59. Not sure of the rules governing proper use of this much talked-about modifier? You’re not alone. After all, the CPT Manual doesn’t offer the most helpful guidance. So today, I’m going to unshroud the mystery surrounding modifier 59—in plain English. (For more advice on recent modifier 59-related denials, be sure to check out this billing FAQ.)


1. When you’re billing for two services that form a National Correct Coding Initiative (NCCI) edit pair—and you provided those services separately and independently of one another.

According to the above-cited CPT document, “Modifier 59 is used to identify procedures/services, other than E/M services, that are not normally reported together, but are appropriate under the circumstances. Documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual.” Holy gobbledygook.

Part of the reason that definition isn’t super relatable to those in the therapy world is that modifier 59 applies mainly to surgical procedures (hence, all the references to incisions, excisions, and lesions). However, there are instances in which it’s appropriate to use modifier 59 in conjunction with rehab therapy services. Recognizing those instances, though, requires you to recognize NCCI edit pairs. To make a long story short, edit pairs—also called linked services—are sets of procedures that therapists commonly perform together. (For a full list of edit pairs, along with guidance as to which ones are modifier 59-eligible, check out this blog post.) If you submit a claim containing both of the codes in an edit pair, you’ll only receive payment for one of the procedures, because the payer will assume that one of the services was essentially “built into” the other.

But what if—for whatever reason—you actually didn’t perform those services together? That’s where modifier 59 comes into the picture. Basically, when you append modifier 59 to one of the CPT codes in an edit pair, it signals to the payer that you provided both services in the pair separately and independently of one another—meaning that you also should receive separate payment for each procedure. Here are a couple of specific examples from compliance expert Tom Ambury of the PT Compliance Group:

  1. Therapists often use modifier 59 to bill for “two timed code procedures [that] are performed sequentially in the same encounter.” For instance, if you billed CPT codes 97140 (Manual Therapy) and 97530 (Therapeutic Activities)—and you provided those services during separate and distinct 15-minute intervals—then, as Ambury explains, “it would be appropriate to add the 59 modifier to the claim submitted for that date of service.”
  2. Therapists also can use modifier 59 to signify that a diagnostic procedure was the basis for performing a linked therapeutic procedure. For example, if a current patient presents with a new diagnosis—one that is different from the diagnosis for which he or she is currently receiving treatment—it would be appropriate to complete a re-evaluation before beginning treatment for the new diagnosis. To signify that you finished the re-evaluation (97164/97168) before beginning treatment—thus making the diagnostic procedure separate from the linked therapeutic procedure—you would apply modifier 59. In doing so, you also are attesting that the results of the re-evaluation led to the appropriate therapeutic treatment and that the diagnostic procedure was not an inherent part of the treatment procedure. (Conversely, if the diagnostic procedure was an inherent part of treatment, you would not bill for the two procedures separately.) Finally—and I cannot emphasize this point enough—you should not routinely use the 59 modifier in conjunction with re-evaluation codes, because doing so could throw up a red flag to your payers.

2. When the payer recognizes NCCI edits.

Speaking of payers, keep in mind that while Medicare adheres to NCCI edits, not all commercial insurances follow suit—at least not completely. As explained here, “Private payers use a combination of NCCI/CCI edits and proprietary edits to determine ‘covered services’ in accordance with payer benefit plans.  Payer payment policies frequently draw from CPT, NCCI/CCI and Medicare as well as applying payer-specific proprietary edits.” Thus, to prevent denials for improper modifier 59 use, be sure to check the list of edit pairs for each individual carrier.

3. When your documentation supports characterizing those services as separate and distinct.

When it comes to telling your patients’ stories, codes and modifiers can only say so much. It’s on you to fill in the plot holes with detailed, defensible documentation. After all, your documentation justifies your billing decisions—and if you’re ever faced with an audit, your notes will be your main source of proof that those decisions were the right ones. That means you should never:

  • append modifier 59 simply because you know it will guarantee more payment.
  • skimp on your documentation—or intentionally document vaguely or misleadingly.  

4. When there isn’t a more descriptive modifier available.

At the beginning of this post, I kind of threw the CPT Manual under the bus for lack of clarity—but there is one point on which it’s a bit less murky: clinicians, coders, and billers should only use modifier 59 as a last resort (i.e., when there’s not a better option). As the CPT Manual states, “...when another already established modifier is appropriate, it should be used rather than modifier 59. Only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used.”

Now, you’ve probably heard talk about the new set of modifiers that CMS created for providers to use in place of modifier 59, when appropriate. As this PT in Motion article explains, “The new modifiers—XE, XP, XS, and XU—are intended to bypass a CCI edit by denoting a distinct encounter, anatomical structure, practitioner, or unusual service.” However, even though these modifiers went into effect January 1, 2015, the APTA has stated that therapists do not need to start using them in place of modifier 59—at least not yet. “We're receiving questions from members about whether they have to use some new modifiers issued by CMS, and the answer at this time is no,” Gayle Lee, JD, APTA senior director of health finance and quality, is quoted as saying in the article. “As of February, 2015, PTs are being instructed that these new modifiers are not required for physical therapist services.” Lee went on to say that therapists may be required to use the new modifiers in the future, so they should keep an eye—or an ear—out for further instruction regarding modifier 59 usage.

So, while PTs probably will never live in the billing-free utopia they’ve always dreamed of, they can make sure the CPT codes and modifiers they use are the ones that most accurately represent the treatments they’ve provided—thus ensuring they receive every cent of payment they deserve.

Download your modifier 59 decision chart.

Enter your email address below, and we’ll send you a super-simple flow chart to help you decide whether it’s appropriate to use modifier 59 in any given billing situation.


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