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Modifier Mayhem: How to Apply Physical Therapy Modifiers (With Examples)

They say that practice makes perfect—so why not practice applying physical therapy modifiers to these perfect billing scenarios?

Melissa Hughes
5 min read
July 25, 2023
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Healthcare billing is a bit of a beast—but you already know that. Between navigating the ICD-10 code book, the CPT codebook with all of its HCPCS codes, and the plethora of billing rules put forth by CMS and other payers, it’s tough to create clean claims. But learning the labyrinthine twists and turns of billing is a necessity to running a successful clinic. 

So we thought it could be helpful to provide you, not with misplaced modifier examples, but with some correctly modified billing scenarios. Read through the following treatment scenarios, and decide how to apply physical therapy modifiers that most often apply to rehab therapists. You can choose from the following: 

  • GP
  • GO
  • GN
  • KX
  • 59
  • 96

Applying Physical Therapy Modifiers: Real-Life Scenarios

1. The Scenario 

During a patient’s appointment for patellofemoral pain, the clinic physical therapist assistant (PTA) provides 13 minutes of therapeutic exercise (CPT 97110), after which the PT provides manual therapy (CPT 97140) for 22 minutes. To close out the session, the PT leads the patient through 15 more minutes of therapeutic exercise.

The Claim

Every service performed by a physical therapist (PT), occupational therapist (OT), or speech-language pathologist (SLP) requires a therapy modifier (GP, GO, GN) for claim submission. So in this scenario, you would affix the GP modifier to the claim. Because a therapy assistant provided a service, the physical therapist assistant modifier (CQ) also comes into play (per CMS’s 2022 final rule). 

Generally speaking, the therapy assistant modifiers apply when a therapy assistant provides more than 10% of a service (though of course there are some exceptions to this rule that you can explore here). In this scenario, apply the CQ therapy modifier to one of the two units of 97110. 

Final modifiers with procedure codes:

  • 97140: GP
  • 97110 (1 unit): GP
  • 97110 (1 unit): GP, CQ

2. The Scenario

After recovering from a broken arm, a Medicare patient develops adhesive capsulitis of the shoulder and seeks treatment from a PT. During one of their treatment sessions, the PT provides manual therapy (CPT 97140) before asking the patient to complete some therapeutic activities (CPT 97530) like reaching up and lifting light-weight objects to eye level. This is followed by ADL training (CPT 97535), such as holding the arm in an elevated position to simulate teeth-brushing and opening and closing cabinets. 

To conclude the session, the therapist provides dry needling (CPT 20560) in the affected area. Since Medicare doesn’t cover dry needling, the therapist issues a voluntary ABN.

The Claim

Since the services performed were provided by a PT who is submitting this claim under their name, affix GP to the claim. Next, take a look at the services provided. CPT codes 97530 and 97535 form an NCCI edit pair. Since they were provided as separate and distinct services, they can both be billed—but one service line will require a 59 modifier. 

Finally, since the therapist issued a voluntary ABN for the dry needling (and since dry needling is a statutorily non-covered service), affix the GX modifier to the claim line with the 20560 CPT code. 

Final modifiers with procedure codes: 

  • 97140: GP
  • 97530: GP, 59
  • 97535: GP
  • 20560: GP, GX

3. The Scenario

A Medicare patient receives a left total hip arthroplasty and receives an outpatient physical therapy plan. The patient’s goal is to discontinue the use of a straight cane with ambulation, so the PT begins with 9 minutes of one-on-one neuromuscular education (CPT 97112), before asking the onsite PTA to oversee the final six minutes of exercises while they briefly step away. The PT returns to instruct the patient in gait training (CPT 97116) and provide follow-up functional testing and administer the Lower Extremity Functional Scale (LEFS) (CPT 97750). 

After the conclusion of the treatment session and while finishing up their documentation, the PT realizes that the patient has exceeded their annual therapy threshold.

The Claim

Let’s start with the therapy modifier. Since these services were provided by a PT who is submitting this claim under their name, affix GP to the claim. Next, let’s look at the contributions of the PTA. Remember that when more than 10% of a service is provided by a therapy assistant, the service line requires a modifier. Since the PTA provided more than 10% of the neuromuscular reeducation service, apply the CQ modifier to that unit. 

Finally, remember that the patient has exceeded their annual therapy threshold. Since their treatment was medically necessary, affix the KX modifier to the claim and bill Medicare as normal.  

Final modifiers with procedure codes: 

  • 97112: GP, CQ, KX
  • 97116: GP, KX
  • 97750: GP, KX

4. The Scenario

A Medicare beneficiary with Ehlers-Danlos syndrome is seeing an occupational therapist to help manage their joint hypermobility. Recently they purchased a wheelchair, and wheelchair training (CPT97542) is in the occupational therapy plan of care. During their first appointment, the OT performs neuromuscular reeducation (97112) for 10 minutes, and then the OT and a certified occupational therapy assistant (COTA) provide wheelchair training in tandem for 11 minutes. The OT steps away, and the COTA provides 12 more minutes of wheelchair training. 

At the end of the appointment, the patient requests manual therapy (CPT 97140) to temporarily soothe their pain. The OT agrees, though they note that they don’t believe the manual therapy is medically necessary and ask the patient to sign an ABN.

The Claim

Because these services were provided by an OT who is submitting this claim under their name, affix GO to the claim. Then, consider the services administered by the COTA. The COTA individually provided 12 of the 23 minutes of wheelchair training, meaning one of the two units of 97542 will require the CO modifier. Finally, because the OT does not believe the manual therapy was medically necessary and because they obtained a signed ABN, affix the GA modifier to the service. 

Final modifiers with procedure codes: 

  • 97112: GO
  • 97542 (1 unit): GO
  • 97542 (1 unit): GO, CO
  • 97542: GO, GA

5. The Scenario

A Medicare beneficiary is seeing a PT for a case of upper-cervical neck pain that they believe is triggering major headaches. They mention at the beginning of their appointment that they think they’ve surpassed their therapy threshold. The PT proceeds with the appointment and provides manual therapy for the cervical spine (CPT 97140) before providing the patient with instruction in ergonomic and postural adaptations (CPT 97537). Finally, the PT performs dry needling to the affected area (CPT 20560) but does not collect an ABN. 

The Claim

Since this treatment was provided by a PT and the claim will be billed under their name, affix GP to the claim form. Because the patient has surpassed the annual therapy threshold, affix the KX modifier to the services that Medicare will pay for (i.e., 97140 and 97537). Finally, because dry needling is a statutorily uncovered service and the PT did not collect an ABN, affix the GY modifier to 20560. 

Final modifiers with procedure codes: 

  • 97140: GP, KX
  • 97537: GP, KX
  • 20560: GY

6. The Scenario

A 47-year-old patient has insurance through a United Healthcare (UHC) Community Plan and has a physician referral for physical therapy services due to an ankle sprain. In a routine treatment visit, the patient receives 15 minutes of manual therapy and 30 minutes of therapeutic activities. 

The Claim

This is a special case due to the payer source—UHC Community Plan. Normally, this claim would be fairly straightforward, requiring only the GP modifier to be added to each code under the billing PT's name. However, the UHC Community Plan has an unusual requirement, mandating the application of modifier 97 for any rehabilitative services (a.k.a. services meant to improve, adapt, or restore function that has been impaired or permanently lost due to an injury or illness).

A Note

While on the topic of the UHC Community Plan’s unique characteristics, we might as well mention that if this scenario was about a habilitative service—used for skills that must be learned or maintained, which are often seen in pediatric settings—rather than a rehabilitative service, then modifier 96 would be used instead of modifier 97.

Final modifiers with procedure codes: 

  • 97140 (1 unit): GP, 97
  • 97530 (2 units): GP, 97

Avoiding denials may feel like a herculean feat, but it’s one that’s totally within the realm of possibility. By applying physical therapy modifiers correctly and knowing rehab therapy billing rules like the back of your hand (or by partnering with someone who remembers them for you), you too can become a clean claims champion. 


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