September 6, 2023

8-Minute Rule Physical Therapy Explained

Learning the Medicare billing guidelines can be overwhelming. These guidelines are structured in a way that prevents overcharging and, at the same time, compensates medical professionals fairly. One of the most misunderstood but vital is the "8-minute rule".

The "8-minute rule" is a billing protocol commonly used in the physical therapy (PT) profession. At its core, the rule ensures that the physical therapist bills the treatment session based on how much time they finished the procedures or modalities. 

Understanding these protocols at an intricate level might be daunting. But don't worry! In this article we will learn about the ins and outs of Medicare billing.


What Is the 8-Minute Rule?

Medicare introduced the 8-min rule way back in April 2000. It can only be used for time-based current procedural terminology (CPT) or direct time CPT codes. These codes are created by the American Medical Association (AMA). 

Direct time codes refer to PT services done directly to the patient. It is billed by how long the whole treatment lasted. Under this, services should be in 15-minute increments to be considered a unit. To bill one unit, the PT must provide at least 8 minutes of service; hence, the name 8-minute rule.

This rule does not apply to service-based codes or untimed codes. Time is not the primary factor in determining the procedure's value. And it's billed the same whether the treatment lasts 5 or 30 minutes. 

What are Service-based CPT Codes?

Service-based CPT codes do not charge by the hour or minute — it is set by a flat rate regardless of how long or short the PT provides the treatment. 

For example, let's say you see a patient with a lower back back in his initial visit. And because it’s his first visit, you evaluate him to decide on his management. 

Evaluation of patients is a standard service-based CPT code. So whether this evaluation takes 20 minutes or an hour, the therapist will bill using a specific CPT code for that evaluation, and the cost remains the same.

What are Time-based CPT Codes?

So unlike service-based, time-based CPT codes are billed by the hours the treatment session took. This means that the longer the PT spends time with the patient, the more units or increments of time can be billed. 

For example, if the PT provided therapeutic exercises and the session’s duration was 15 minutes, then that's 1 billable unit. But if the PT added 15-minute gait training to that, then that's 2 units, and so on.

Who Uses the 8 Minute Rule?

Physical, speech, occupational therapists, and other healthcare clinicians deliver outpatient services. These clinicians rely on the Medicare 8-minute rule when billing, as this rule is explicitly tailored for direct time CPT codes.

The rule of 8s is essential to private practices, skilled nursing, and rehabilitation services. 

Beyond billing, the 8-minute rule therapy protects the patient's rights. It acts as a regulatory mechanism in preventing overcharging, ensuring the patients receive the necessary care. 


How Does the 8-Minute Rule Work?

Medicare copyrighted this 8-minute rule PT billing system to adequately reimburse time-based services. You need to treat the patient for at least eight minutes. If the service lasts 7 minutes or less, Medicare won't cover it.

So, when calculating, Medicare sums up the total minutes of one-on-one skilled therapy and divides it into 15 minutes. So, let's say the entire treatment session is 45 minutes.  

Then that's 45 ÷ 15= 3 units.

So what if after this division, there's a remainder of 8 minutes or more, you can bill for an additional unit. But if the remainder is 7 minutes or less, you cannot bill for that time.

Continue to read to see more examples below!


Which Situations are Covered by the Rule?

The physical therapy 8-minute rule applies to direct services, meaning it is a one-on-one direct contact of PT with the patient. The PT must be there in person to deliver the service, let's say stretching exercises.  

Additionally, if the PT gives multiple direct services within the day, you can total the hours and bill Medicare appropriately.

It is important to note that some services might not require the continuous attendance of the PT, like when a patient has an electrical stimulation machine. And if the direct services do not hit the 8-minute mark, you can not bill that for 1 unit. 


Service-Based vs. Time-Based CPT Codes

Service-based and time-based CPT codes differ in billing services for Medicare. As mentioned above, time-based is billed based on the duration and time spent during the session. 

On the other hand, when you use a service-based CPT code, you bill for one unit regardless of how long it takes to complete the service or intervention. So, these codes are not subject to the 8-minute billing rule. 

Here are some examples of serviced-based codes in physical therapy or rehabilitation:

(97161-97163) Initial Evaluation: Evaluation is divided into low, moderate, and high. The charge is fixed during this time regardless of the evaluation's length.

(97010) Hot/Cold Packs: PT can set the modality and leave the patient. 

(97012) Mechanical Traction: Utilizing devices to traction the spine for several minutes does not need PT's presence.

(97018) Paraffin Bath: Use a paraffin wax bath on different body areas like the hands and feet. Again, PT sets up and leaves the patient for a few minutes. 

Here are some examples of time-based codes in physical therapy or rehabilitation:

(97110) Therapeutic Exercises: Techniques PT implements for strength, endurance, range of motion exercises, etc.

(97140) Manual Therapy: Techniques comprising soft tissue mobilization, lymphatic drainage, and manual traction with PT's presence. 

(97116) Gait training: PT one-on-one treatment, training patients to walk and other mobility exercises. 

(97112) Neuromuscular Re-education: PT techniques that improve movement, balance, coordination, etc.

Knowing the differences and which category PT modalities belong to is crucial, as sometimes interchanging codes lead to billing disputes. So, simply put, the pt 8-minute rule is not used in serviced-based codes because time is not a factor when determining billing. However, it is only used in time-based services where time is considered when billing treatments. 


Minute Rule Chart and Billable Units

Below is a chart that shows the total number of timed minutes and the number of units you can bill based on that total. 

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 minutes 

6 units


Always begin with identifying where the duration of the units falls. Let's say your treatment lasted 19 minutes; then you can bill 1 unit for that as it falls between 8-22 minutes. 

Remember that the interval with breaks where you did not provide a direct service should be left out of the total hours you will bill.

 For example, the patient had hot packs of 20 minutes duration and therapeutic exercises of 30 minutes. 

Then that's only 30 minutes, which you can bill for 2 units.


How Do I Calculate Billable Units?

The 8-minute billing rule calculates billable units in time-based code services like physical therapy treatments. So, the rule stipulates a corresponding unit for a particular duration of the modalities used.    

There are two main methods for determining these units:

Method 1: Use the designated chart provided above. Always begin with identifying where the duration of the units falls. Let's say your treatment lasted 19 minutes; then you can bill 1 unit for that as it falls between 8-22 minutes. 

Alternatively, you can divide the total hours by 15. So if the session lasted for 30 minutes, then that's 30 ÷ 15= 2 units. 

Method 2: If you provided multiple services daily, that did not equate to 8 minutes. Then, you can combine those services, add them up, and determine how many billable units. For instance, if you gave gait training for 5 minutes and stretching exercises for 7, that's 12 minutes, which equals 1 billable unit. 

What Are Mixed Remainders?

According to Medicare, "mixed remainders" are hours left from multiple timed services that do not meet the 8-minute threshold. 

These leftover hours from different services can be combined and billed as units. 

During a post-op treatment session, you provided the following:

  • Therapeutic Exercise: Focused on knee flexion and extension for 12 minutes.

  • Neuromuscular Re-education: Targeted at improving her gait pattern for 7 minutes.

  • Manual Therapy: Applied to decrease knee joint stiffness for 6 minutes.

So upon billing, that's 12 + 7 + 6 = 25 minutes with a remainder of 10 minutes, which exceeds the 8-minute mark, so this treatment session can be billed as 2 units. If the leftover hours of different modalities reach 8 minutes, Medicare will allow procedures to be billed as 1 unit. Make sure that you bill for the highest duration of treatment, which in the case above is the neuromuscular re-education. 


8 Minute Rule Physical Therapy Examples

Let's take a look at more 8 min rule PT examples below:

Example 1: Treatment less than 8-minutes

Under the billing guidelines, a minimum of 8 minutes is typically required to bill for one service unit. So, if you provided the patient 5 minutes of massage, this session is not qualified for 1 billable unit. 

Example 2: Combining serviced-based and time-based with different durations

PT gave evaluation to a low back pain patient accounting for 15 minutes, 15 minutes of hot packs and 30 minutes of therapeutic exercises. 

The evaluation is a service-based code and the hot packs are both serviced based codes so regardless how much time they took it is only billed as 1 unit. However on the other hand the therapeutic exercises are considered as time based codes and it stretched up to 30 minutes so naturally it will be billed as 2 units. So even though this whole session is 60 minutes, you have to consider if you provided a mix of serviced based and time based services. 

Example 3: Multiple time-based services 

Now, you are treating a patient with a frozen shoulder. The patient received 10 minutes of ultrasound therapy, 20 minutes of therapeutic exercises, and 10 minutes of manual therapy sessions. 

And since every procedure is a time-based code. The treatments apply to the 8-minute rule. You can just add them all up, like 10+20+10= 40 minutes. According to the minute rule chart, it ranges between 38 – 52 minutes, so the whole session can be billed as 3 units. 


Does Assessment and Management Time Count Toward the PT 8-Minute Rule?

No. It doesn't count toward the 8-minute rule. Assessing and management are fundamentally different from actual one-on-one care. Also, CPT codes already include the time for assessment and management. If you are billing for a manual therapy procedure that already involves some degree of evaluation or management.

But if you want them to be included when billing, document it intricately. Clear documentation that supports rigorous assessment, nature of the management, patient status, what's the overall care plan, and how it affects the patient's progress. 

You already know that in healthcare, the justification for billing lies within the documentation. If you don't document it, it didn't happen, right? So, make sure to be as detailed as possible to prevent any disputes during audits.


How Can We Avoid 8-Minute Rule Physical Therapy Mistakes?

Ensuring accurate service billing is essential as this fosters fair compensation and patient trust. Integrating advanced tools in your practice, such as EMR like PtEverywhere, can avoid these mistakes. The ability to document treatment anytime and any place decreases the chances of errors like overbilling or undercharging. By utilizing these tools, your practice can improve billing processes and reinforce transparency and professionalism in patient care.