What Is a PT Modifier in Physical Therapy Billing?

Medical coding modifiers provide additional details about healthcare services, clarifying specific circumstances without altering the primary code’s definition. In physical therapy, the CQ modifier indicates services provided by a Physical Therapist Assistant. While “PT modifier” might colloquially suggest a modifier related to physical therapy, CQ is the accurate code for services involving a Physical Therapist Assistant.

Understanding the CQ Modifier

The CQ modifier designates that outpatient physical therapy services were furnished, either in whole or in part, by a Physical Therapist Assistant (PTA). This Level II Healthcare Common Procedure Coding System (HCPCS) code, developed by the Centers for Medicare & Medicaid Services (CMS), distinguishes services performed by a PTA from those delivered directly by a licensed Physical Therapist (PT). This distinction is important for accurate billing, compliance, and appropriate reimbursement.

The CQ modifier informs payers that a PTA was involved in providing the care. This detail is essential because the scope of practice and supervision requirements for PTAs can differ from those for licensed PTs, impacting how services are recognized and paid for. Proper application ensures transparency in the billing process and helps healthcare providers adhere to specific guidelines, particularly those set by federal programs like Medicare.

When to Use the CQ Modifier

The CQ modifier is applied to claims when a Physical Therapist Assistant (PTA) provides physical therapy services. For Medicare beneficiaries, this modifier is required for outpatient therapy services furnished by a PTA in various settings, including private practices, skilled nursing facilities, home health agencies, and outpatient hospital departments. A core guideline for applying the CQ modifier involves the “de minimis” standard: if a PTA furnishes more than 10% of a unit of service, the CQ modifier must be appended to that service line. This standard applies to both timed and untimed codes, ensuring even partial involvement by a PTA is reported.

Supervision rules also influence when the CQ modifier is necessary. While state laws dictate general supervision levels for PTAs, Medicare has specific billing requirements. For instance, Medicare shifted to a general supervision standard for PTAs in outpatient settings, effective January 1, 2025, allowing the PT to be available by telecommunication. Regardless of the supervision level, if a PTA delivers services that meet the de minimis threshold, the CQ modifier must be used to accurately reflect their involvement.

Impact on Reimbursement

Using the CQ modifier has a direct financial consequence for physical therapy services. For claims on or after January 1, 2022, Medicare implemented a reduced payment rate for services furnished in whole or in part by a Physical Therapist Assistant (PTA) or Occupational Therapy Assistant (OTA). These services are reimbursed at 85% of the otherwise applicable Medicare Physician Fee Schedule amount. This means that services billed with the CQ modifier will receive a 15% reduction in payment compared to services provided entirely by a licensed Physical Therapist.

This payment reduction applies to various institutional therapy providers and private practices when PTA services meet the de minimis standard. The policy aims to differentiate professional involvement and ensure appropriate compensation based on provider credentials. While Medicare mandates this reduction, other commercial insurance plans may have their own policies regarding PTA services and reimbursement. Accurate CQ modifier use is essential for compliance and to avoid claim denials or payment delays.