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  • Writer's picturePatientStudio

The Comprehensive Guide to Physical Therapy Modifiers

One of the critical aspects of PT billing is the use of Physical Therapy Modifiers. Coding errors, which can include improper modifier usage, are one of the most common reasons for claim denials.This guide aims to provide an in-depth understanding of what these modifiers are and how they can help ensure proper reimbursement for the services provided.

PT Modifiers Thumbnail

What are Physical Therapy Modifiers?

A Physical Therapy Modifier is an alphanumeric codes added to CPT (Current Procedural Terminology) codes during billing. These modifiers provide additional information on the services provided, which helps in processing claims and ensuring proper reimbursement.

Modifier on CMS-1500 form

Classification of Physical Therapy Modifiers

Physical Therapy Modifiers are primarily classified into two categories:

  1. CPT Modifiers: These are two-digit codes that correspond to CPT codes.

  2. Level II HCPCS Modifiers: These consist of two-letter codes used by Medicare, some Medicaid, and commercial plans.

Commonly Used Physical Therapy Modifiers

GP Modifier

The GP modifier is used in billing to indicate that a service has been provided by a physical therapist.

GP Modifier Example:

The GP modifier is used in any case where the rendering provider is a physical therapists. If physical therapist provides a therapeutic exercise (CPT code 97110) in an outpatient setting, they would bill for this service as "97110-GP" to denote the provider of the service.

Modifier 59

Modifier 59 signifies that a distinct service or procedure was performed separately from another non-evaluation and management service. It's vital in ensuring that both services comply with the National Correct Coding Initiative.

59 Modifier Example:

Suppose a PT is treating a patient with an ankle sprain, billing for 15 minutes of manual therapy (CPT code 97140) and 15 minutes of therapeutic activity (CPT code 97530) on the same date. Adding the 59 modifier to code 97530 ensures that payment is received for both timed codes, provided they were performed during separate 15-minute increments.

KX Modifier

The KX modifier is used when services provided to a patient exceed Medicare’s therapy threshold. This modifier ensures that continued treatment is justified with appropriate documentation in the patient's medical record.

KX Modifier Example:

If a patient was treated for a hip fracture early in the year and hit the therapy threshold, but the patient requires therapy beyond that threshold, the therapist applies a KX modifier to justify continued care.

GA Modifier

The GA modifier indicates that a required Advance Beneficiary Notice of Noncoverage (ABN) is on file for a service considered not medically necessary. This allows the provider to bill a secondary insurance for non-Medicare-covered services or bill the patient directly.

GA Modifier Example:

If a Medicare patient has reached a functional plateau after six weeks of post-op services but still wishes to attend PT for maintenance, the GA modifier allows the clinic to continue billing secondary insurances or bill the patient directly.

XE Modifier

The XE modifier, short for "Separate Encounter", is used to indicate a service that is distinct because it happened during a separate encounter on the same Date of Service (DOS). This modifier is utilized when a patient has multiple encounters with a provider in a single day, with each encounter representing a unique service.

XE Modifier Example

a patient might visit a physical therapist in the morning for a routine follow-up and then return in the afternoon for a separate case/issue related to a different body part. In this scenario, the second service would be billed with the XE modifier to denote it as a separate, distinct encounter from the morning session.

XP Modifier

The XP modifier - "Separate Practitioner," is used to indicate that a service was performed by a different practitioner.

XP Modifier Example

A patient receives physical therapy services in the morning for a specific issue and then returns to see an occupational therapist for separate services, the second service would be billed with the XP modifier to denote it as a separate, distinct encounter from the first session. This modifier helps ensure accurate billing and proper reimbursement for the services provided by different practitioners.

CQ Modifier

One of the most common modifiers for physical therapy, the CQ modifier denotes that services were performed by a Physical Therapy Assistant (PTA).

CQ Modifier Example

A patient is seen by a physical therapy assistant for a routine/daily session. The CQ modifier will be appended to all physical therapy services or charges provided by the PTA. The PT must cosign the PTA's notes as the rendering provider.

Other Noteworthy Modifiers

There are several other modifiers used in PT billing, including:

  • Modifier -22: Applied when the service provided is significantly above the average.

  • Modifier -52: Used when the service is reduced or less than expected.

  • Modifier -95: Applied when PT services are provided via telehealth.

  • Modifiers -96 and -97: Used when the PT services are habilitative and rehabilitative in nature, respectively.

  • Modifiers CO: This indicates a Certified Occupational Therapy Assistant (OTA) performed the therapy service.

Understanding CCI Edits

CCI (Correct Coding Initiative) Edits are another crucial aspect of PT billing. They consist of a list of CPT codes billed in PT, stating any codes that can't be billed on the same service date without using a modifier. Staying up-to-date with the CCI edits list is vital to avoid claim denials.

Modifiers and EHRs

Having an Electronic Health Records (EHR) system that integrates with your billing tool is crucial for maintaining easily accessible client chart notes and ensuring proper diagnostic and procedural codes for billing. This integration can reduce errors, speed up the insurance billing process, and ensure proper reimbursement for the services provided.


Modifiers play a significant role in PT billing. They help ensure that PTs receive payment for the services provided while guaranteeing compliance. However, it's essential that the usage of any modifier is supported by documentation, reflecting medically necessary and skilled care. By understanding the use of Physical Therapy Modifiers, PTs can steer clear of billing errors and claim denials, ensuring proper reimbursement for their services.

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