Understanding the Physical Therapy 8-Minute Rule

It’s important for physical therapists (PTs) who bill Medicare to understand the physical therapy 8-minute rule and how it applies to calculating billing units for physical therapy. 

The 8-minute rule is the backbone of Medicare billing, determining how many billable units of treatment can be charged for time-based services during an individual date of service. 

The 8-minute rule was instituted in 2000, with the primary goal of reducing fraudulent billing by clinicians for services provided. 

The overarching purpose of the 8-minute rule is to: 

• Ensure patients get the adequate that they need 
• Protect the patient’s rights
• Avoid overcharging 
• Ensure quality and continuity of care for all patients 

As PTs, it is essential to become an expert in understanding  the physical therapy 8-minute rule—which is integral in treatment, documentation, and billing for Medicare patients. 

The 8-minute rule protects all parties—including the provider. By providing a clear format for physical therapy billing units, there will be fewer denials of claims. Thus, the provider will have timely reimbursement from Medicare. 

By utilizing the physical therapy 8-minute rule, providers can ensure that they’re fully reimbursed for a majority of time-based services they provide.  The 8-minute rule applies primarily to Medicare, a government-based, national health insurance program that was created in 1965 under the Social Security Administration (SSA). 

Medicare primarily provides health insurance for people ages 65 and older, but may also cover people under 65 who are on disability (according to the SSA). 

In addition, other public insurance payers that use the 8-minute rule and corresponding billing units for physical therapy (and other specialties) include Medicaid, TRICARE, and CHAMPVA.

Medicaid is the federal and state funded health insurance plan that is provided for low-income individuals and households.

TRICARE is a Department of Defense (DOD) health care program that provides medical insurance benefits to military personnel and retirees, as well as their dependents.

CHAMPVA is also a government backed health insurer, under the Veterans Administration (VA), that insures military veterans and their dependents. 

All four insurance companies value quality of medical care, and appropriate billing to support the insured, by utilizing the 8-minute rule. Adherence to the 8-minute rule standardizes the quality and quantity of care being provided through federally funded programs.

8-minute rule examples

Physical therapists can apply the physical therapy 8-minute rule to patient care across a multitude of clinical settings, including: 

• Private practice
• Outpatient practice 
• Skilled nursing facilities (SNF)
• Rehabilitation facilities 
• Home healthcare

Care provided by physical therapy assistants under physical therapy supervision, is also subject to the 8-minute physical therapy rule. 

Other care providers that use the 8-minute rule include respiratory therapists, speech language pathologists, and occupational therapists, who all bill Medicare, TRICARE, or CHAMPVA. The 8-Minute rule does not apply to group therapy in a rehabilitation, SNF, or similar clinical setting.

According to the Consolidated Appropriations Act of 2023, under the Centers for Medicare and Medicaid Services (CMS), Medicare will reimburse physical therapists (and physical therapy assistants) for telehealth care through December 31, 2024. 

Prior to the passing of this bill, CMS would pay for telehealth outpatient therapy services for 151 days after the end of the public health emergency for COVID-19. Of course, due to the ever-changing post-COVID landscape, these guidelines may be subject to change.

The following list includes physical therapy codes that are eligible to be used for reimbursement for telehealth physical therapy services (note that these codes are both time-based and service-based CPT codes):

• PT evaluation (CPT code 97161)
• PT reevaluation (CPT code 97164)
• Therapy procedures using exercise/therapeutic exercise (CPT code 97110)
• Neuromuscular reeducation (CPT code 97112)
• Therapeutic procedures (CPT code 97116)
• Therapeutic activities (CPT code 97530)

When billing Medicare under the 8-minute rule, a billing unit is a measure of medical services provided. Insofar as Medicare billing, a single, time-based unit of service lasts anywhere between 8-22 minutes, for that specific date of service. 

Additional time-based billable units for services provided on that date of service are calculated in 15-minute increments. 

This rule only applies to time-based CPT codes, or Current Procedural Terminology®, and offers providers a uniform language of coding services to streamline reporting, as well as to increase accuracy and efficiency of coding. It is important to note that both an 8-minute session and a 22-minute session of time-based treatment qualify as one unit. 

Similarly, if that same treatment lasts 25 minutes, the therapist can bill two units. 

8-minute rule calculator 

The following table serves as an 8-minute rule calculator for time-based billing units for physical therapy and other specialties:

• 8-22 minutes — 1 unit
• 23-37 minutes — 2 units
• 38-52 minutes — 3 units
• 53-67 minutes — 4 units 
• 68-82 minutes — 5 units
• 83-97 minutes — 6 units
  

After treating a patient, you can calculate billable units by using the physical therapy 8-minute rule via the following steps:

1. Add all the time spent (in minutes) on time-based services for one date of service. This will help you determine how many units you can bill for in total.
   
2. Separate out each whole 15-minute unit by specific CPT code and use the 8-minute rule chart to determine how many units you can bill for each service provided.
   
3. If there are any remaining minutes that have not been converted into units, these are your “remainder minutes” or “mixed remainders.” Medicare allows billers to borrow/round up other services to create whole units if there are enough “remainder” minutes. Add whatever “remainder” minutes you have to any incomplete whole units. For example, 5 leftover therapeutic exercise minutes can be added to 10 minutes of manual therapy units, to equal 15 minutes of service, or 1 unit. The CPT code to be billed will always be based on the treatment with the largest remainder. In this case, it would be coded as manual therapy. 

Please note: If a provider performs a treatment that lasts only seven minutes, that treatment alone would not qualify as a unit and the provider would not be reimbursed for this work. However, this example is why Medicare allows for “remainder minutes” and the ability to combine minutes for different time-based treatments performed. 

The 8-minute rule is specific to all interventions where the provider has direct contact with the patient. The 8-minute rule does not include group care. 

Time-based vs. service-based CPT codes

The following is a list of direct, time-based CPT codes commonly used by PTs:

• Manual electrical stimulation (CPT code 97032)
• Ultrasound (CPT code 97035)
• Therapeutic exercise (CPT code 97110)
• Gait training (CPT code 97116)
• Manual therapy (CPT code 97140)
• Neuromuscular reeducation (CPT code 97112)
• Neurological reeducation (CPT code 97113)
• Therapeutic activities (CPT code 97530)
• Iontophoresis (CPT code 97033)
• Prosthetic training (CPT code 97761)
• Self care/home management (CPT code 97750)

Time-based treatment will include preparation time for things required for care. It also allows providers to include time management, assessment, and education for the patient about their condition, as part of the definition of each code. 

Examples of these billable minutes include:

• Documenting actions in the patient’s presence during the visit
• Answering patient questions about care/impairment/case
• Counseling and education around self care to perform at home
• Assessing and managing patient response to treatment in real time

Per the American Physical Therapy Association (APTA), the key to justifying your decision to bill for assessment and management time lies in the documentation. Documentation must be thorough, must accurately describe the treatment, and must defend and support the provider’s clinical reasoning. 

In addition to time-based CPT codes, there are service-based CPT codes. Service-based codes cover procedures and services in which the provider does not have sustained, one-on-one constant contact with the patient. 

When billing service based, or procedural, codes, the rule is to always bill one unit, regardless of how long the procedure takes. There is no associated time requirement for these codes. 

Examples of service-based CPT codes for physical therapy include:

• PT evaluation (CPT code 97161)
• PT reevaluation (CPT code 97164)
• Electrical stimulation (unattended) (CPT codes 97014/G0283)
• Hot/cold packs (CPT code 97010)

8-minute rule vs. “rule of eights”

It should be noted that the 8-minute rule is not the same as the American Medical Association (AMA) “rule of eights.” Instead of adding the total session time for all time-based codes used, the “rule of eights” considers each individual unit. A clinician cannot bill for a unit unless the one-on-one treatment lasted at least 8 minutes. Per the “rule of eights,” culminating minutes or remainder minutes do not apply. 

The “rule of eights” still counts billable units in 15-minute increments, but instead of combining time from multiple units, the rule is applied separately to each unique service. The concept of mixed remainders does not apply. If a provider performs eight minutes of therapeutic exercise and eight minutes of manual therapy, per the “rule of eights,” that would equal two units. 

If a patient received seven minutes of therapeutic exercise and 23 minutes of neuromuscular rehabilitation, per the “rule of eights,” that would be reimbursed as one billable unit. 

Conversely, per the 8-minute rule, and the remainder minutes, that would be reimbursed as two billable units. 

When using the physical therapy 8-minute rule, a provider must consider how to navigate this complex timekeeping model in order to reduce the number of billing (and therefore, reimbursement) errors. Certain billing situations further complicate your calculations, particularly when it comes to exact documentation to serve and justify billing. 

Familiarizing yourself—and being extremely thorough—with all documentation requirements is key. 

Be mindful of mixed remainders and use the chart above to calculate units and prevent unintentional billing errors and lapses in insurance payment. 

Remember to distinguish which codes are service-based and which are time-based.

When in doubt, refer back to the APTA or CMS guidelines to understand the best route in documenting and calculating billable units. 

With consistent accuracy and attentiveness, you will become an expert biller for Medicare, Medicaid, TRICARE, and CHAMPVA.

How SimplePractice streamlines running your physical therapy practice 

SimplePractice is HIPAA-compliant physical therapy practice management software with everything physical therapists need from booking to billing.

With SimplePractice physical therapists can accept and schedule client appointments, take secure notes, and process patient payments from their phones or computers.

Try SimplePractice free for 30 days. No credit card required.

READ NEXT: 8-Minute Rule Cheat Sheet