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New Year, New Rules Pt.2: Clinical Unit Rules For Therapy

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Soriah Esquivel

Welcome to part 2 of our “New Year, New Rules” #rtblogseries! With the finalized Physician Fee Schedule (PFS) rules for 2022, there’s a lot of changes to cover and explain. That's why we’ve gathered all the essential information regarding billable units and modifiers to make sure you aren’t caught off guard when it comes to receiving payments. Let’s go over the basics together.

Clinical Unit Rules Acronyms

What Is The 8-Minute Rule and Why Is It Important?

The 8-minute rule is a Medicare billing criteria that applies to time-based CPT codes for outpatient, in-person services. It’s important for providers to understand how this rule works, so that they can minimize billing errors and potentially avoid the enormous hassle of underbilling or delayed reimbursement issues.

What Is A Unit?

This particular rule requires providers to bill Medicare patients in units of service, where a single unit represents 15 minutes of clinical care. Of course, not every appointment can be perfectly divided into 15 minute units, so, fortunately, there is an official process on how to measure those in-between moments!

If a provider facilitates between 8 to 22 minutes of service, that visit will be rounded to 15 minutes or one unit for billing purposes. However, if a provider gives 23 to 37 minutes of service, this equates to 2 units while 38 to 52 minutes is 3 units and so on, so forth. Take a look at the table below for a visual representation of how these units are measured.


Minutes of Service

Number of Units

8 - 22


23 - 37


38 - 52


53 - 67


68 - 82



When Should The 8-Minute Rule Be Followed?

While dubbed as “Medicare’s 8-minute rule”, this rule is actually the standard for all federally funded plans, including Medicaid and Tricare. In fact, some commercially funded plans choose to use these billing rules as well. Furthermore, Raintree’s platform offers tools to track specific billing criteria as well as allows the ability to individually manage rules for each patient, no matter what plan they are on.

Modifiers and When To Apply Them

If you are an Occupational Therapist (OT), Physical Therapist (PT) or therapy assistant to either kind, you’re very likely going to run into modifiers. In 2020, CMS established two modifiers in particular for PT and OT assistants:

  • CQ: Outpatient physical therapy services furnished in whole or in part by a physical therapist assistant (PTA)
  • CO: Outpatient occupational therapy services furnished in whole or in part by an occupational therapy assistant (OTA)

There are two situations that call for these modifiers:

  1. When a PTA/OTA furnishes the entire service independent of a PT/OT
  2. When a PTA/OTA furnishes a portion (or unit) of service that exceeds 10% of the total minutes for the care that has been provided. This 10% is known as the de minimus standard, which also came about in 2020. 

Already Familiar With The 8-Minute Rule Basics? 

Here are a couple of new changes you should be aware of: 

Per the 2022 Physician Fee Schedule (PFS) rulemaking, several revisions have been made that introduce scenarios where the CQ/CO modifiers or the de minimus policy would be changed or not applicable at all.

  1. If a PTA/OTA provides independent care to a patient, but the PT/OT renders at least one unit of service on their own, without the minutes of services provided by the PTA/OTA, the CQ/CO modifier does not need to be added to the bill.
  2. When there are two billable units where the therapist and the therapist assistant each provide between 9 to 14 minutes of the same service or if the service adds up to at least 23 minutes (but no more than 28 minutes), the de minimus policy would not apply. In this unique situation, one unit is to be billed with the CQ/CO modifier for the minutes furnished by the PTA/OTA, while the other unit should be billed without the CQ/CO modifier.
  3. The de minimis policy has been revised to include a “different time interval” in addition to the standard 15-minute unit. This accommodates two new codes that were introduced for Remote Therapeutic Monitoring (RTM) Services: CPT codes 98980 and 98981. These codes are measured in 20 minute units.

CMS lists examples of these scenarios on their website as well as a more in-depth look at how to calculate de minimus (there’s more than one way!) and when to use modifiers. Review these amendments thoroughly to stay prepared for any billing situation that comes your way.

Next week we will be going over the finalized changes made to the No Surprises Act and what those adjustments will mean for providers and patients without insurance, so keep an eye out for our next post in this three part #rtblogseries!

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