The season of spooks has officially passed—and uncanny thrills and chills (like dancing skeletons and pumpkin people) have retreated to their hovels for another year. But one eerie (and stubborn) sentinel of the season still remains: the PTA and OTA modifiers and payment reductions. This spooky surprise (courtesy of CMS) may not have been the spookiest thing to pop up around Halloween time this year (I personally thought the 8% payment cut was a lot scarier), but it still created a lot of trepidation and unease—in part because applying the modifiers is kind of complicated. Luckily, I can help you conquer that fear by teaching you exactly when to apply these assistant modifiers. Get ready to grab a pencil and paper and dust off your algebra skills, because we’re gonna do some light number-crunching.  

What are the PTA and OTA modifiers?

Let’s recap. In 2018, CMS unveiled a new reimbursement policy for PTAs and OTAs. Beginning in 2020, when a therapy assistant provides a service “in whole or in part,” the service line on the Medicare Part B claim must include one of two payment modifiers: CQ (for PTAs) or CO (for OTAs and COTAs). Then, once 2022 rolls around, CMS will begin reducing reimbursements for services that have an assistant modifier by 15%. 

As per the 2020 final rule, these modifiers will apply to all outpatient services that are paid under the Medicare Physician Fee Schedule—including those provided inpatient facilities (e.g., CORFs, SNFs, and HHAs). These modifiers will also apply to those who provide outpatient services in rural and underserved areas. However, these modifiers will not apply to services furnished in critical access hospitals or billed incident-to a physician or NPP.

When do we apply them?

This is where things start to get a little hairy. It’s easy enough to determine whether an assistant provided a whole service—but it’s a little tougher to figure out whether an assistant provided a service “in part” based on CMS’s de minimis specifications. What it boils down to is this: when a therapy assistant provides more than 10% of a service, that service is considered to have been delivered “in part” by the assistant—meaning the associated claim line must contain an assistant payment modifier. 

However, as per the 2020 final rule, only the minutes that a PTA or OTA treats independently from the therapist will count toward the 10%. In other words, when a therapist and an assistant provide treatment at the same time, the assistant modifiers will not apply. 

CMS shared two algebraic methods in the proposed rule that providers can use to determine whether or not they need to apply an assistant modifier. One of the methods is great for math-focused number wizards, and the other is what I like to call the path of least resistance. 

Method One (a.k.a. Mathapalooza for Number Wizards)

To use the Mathapalooza method (which I personally do not recommend), follow these four steps

  1. Divide the number of minutes that a PTA or OTA independently furnished a service by the total number of minutes the service was furnished as a whole. 
  2. Multiply that number by 100. 
  3. Round to the nearest whole number. 
  4. If the final total is 11% or greater, apply the CQ or CO modifier.

Let’s run through an example so you can see how the math plays out: say a PT and a PTA are providing gait training to a patient, tag team-style. The PTA provides the first four minutes of the service on his or her own, and the therapist furnishes the last 11 minutes. 

In this case, you would divide the number of minutes that the PTA furnished the service (four) by the total length of the service (15). This comes to 0.2667, which you’ll then multiply by 100 (26.67%) and round to the nearest whole number (27%). Because the final number is higher than 11%, you’ll apply the CQ modifier. 

Method Two (a.k.a. The Path of Least Resistance)

The second method is, thankfully, a little bit simpler—and much easier to do without a calculator.

  1. Divide the total number of minutes that the service was furnished by ten. 
  2. Round to the nearest whole number. 
  3. Add one minute to the total. 
  4. If the PTA or OTA furnished care independently of a therapist for longer than the final total, apply the CQ or CO modifier. 

Let’s run through the same example from above with this method. Divide the total number of minutes that the service was furnished (15) by ten. You’re left with 1.5, which you’d then round up to the nearest whole number (two). Add one to that number for a final total of three minutes. If the PTA independently provided three or more minutes of service—as is the case in this example—then you’d apply the CQ modifier.  

What are some examples of this in action?

I’m going to run through all of the following examples—taken from the 2020 proposed rule and modified to fit CMS’s new definition of “in part”—using the path of least resistance (i.e., the second calculation method). Although both methods will accurately tell you whether or not to apply a CQ or CO modifier, I strongly, strongly recommend—and really cannot emphasize enough—that you should choose the calculation method that puts the least amount of burden on your clinic. 

Example One

An OT and an OTA work together to provide a patient with therapeutic exercise (CPT code 97110). The OT independently provides the first seven minutes of the service, and the OTA independently provides the last seven minutes. In total, the patient receives 14 minutes of therapeutic exercises. 

Math

First, divide the total length of the service (14 minutes) by ten. You’re left with 1.4, which you’d round to the nearest whole number—one. Add one minute to that whole number for a final total of two minutes. If the OTA provided more than two minutes of this service, then the CO modifier must be applied to the claim. 

Do you need to apply a CO modifier? Yes. 

Example Two

A PT and PTA work concurrently as a team to provide a patient with neuromuscular re-education (CPT code 97112) for a grand total of 30 minutes. 

Math

Trick question alert! Since the PT and PTA provided the service in tandem (and the PTA did not furnish 10% of the service on his or her own) the PTA modifier is not required on the claim. 

Do you need to apply a CQ modifier? No. 

Example Three

A PT and PTA work together to treat a patient. The PT independently provides manual therapy (97140) for 15 minutes, and the PTA independently provides therapeutic exercise (97110) for seven minutes. Altogether, the patient receives 22 minutes of treatment, which only accounts for one billable unit per the 8-minute rule.   

Math

This is one of those funky scenarios where you actually don’t need to do any math to figure out whether or not you need to apply a CQ modifier. In this example, the PT can only bill one service unit—and by CMS’s own rules, you’d bill the unit that took the most time (i.e., 97140). Because the PTA did furnish any part of that particular service, you would not need to apply the CQ modifier.

Do you need to apply a CQ modifier? No. 

Example Four

An OT and a COTA work together to treat a patient. The OT independently provides the patient with seven minutes of manual therapy (97140), and then the COTA independently provides that patient with seven minutes of therapeutic exercise (97110). In total, the patient receives 14 minutes of treatment, which equates to one billable unit. 

Math

This is another scenario where you don’t actually have to do any math to figure out whether you need to use the CO modifier. Since the OT and COTA provided two separate services for an equal number of minutes, the OT would break the tie, and one unit of 97140 would be billed without the CO modifier. 

Do you need to apply a CO modifier? No. 

Example Five

A PT provides a patient with 32 minutes of neuromuscular re-education (97112). The PT then works with the patient for 12 minutes on therapeutic exercise before handing the patient over to a PTA, who independently provides another 14 minutes of 97110. Then, the PTA independently provides the patient with 12 minutes of self care and home management training. In total, the patient receives 70 minutes of treatment, which equates to five billable units. 

Math

The first thing you need to do is divvy up the billable units by service. You can bill two units of neuromuscular reeducation (97112), two units of therapeutic exercise (97110), and one unit of self care and home management training (97535). 

Let’s start with the trickiest part of this scenario: the therapeutic exercise units. In total, the patient received 26 minutes of 97110. If you divide 26 minutes by ten, you’re left with 2.6 minutes. After you round up and add one, you’re left with a healthy four minutes. Because the PTA independently provided more than four minutes of 97110, both units would require a CQ modifier if you billed them on the same claim line. 

However, in the final rule, CMS allowed therapists to split up codes on claims in order to reduce the impact of modifier application. So, on this particular claim, you could split up the two units of 97110 and only apply the CQ modifier to one of them. 

Luckily, the other units in this example are pretty clear cut. The two units of 97112 were not provided by the PTA, so they do not need the CQ modifier. However, the single unit of 97535 was provided solely by the PTA, so it actually does need a CQ modifier. 

Do you need to apply a CQ or CO modifier? Yes (to 97535 and one unit of 97110)

Do I need to include any extra documentation to justify the inclusion or omission of the PTA and OTA modifiers? 

Nope! In the final rule, CMS decided to forgo the additional documentation requirements that it initially proposed, stating therapists’ documentation should already be thorough enough to justify the use or omission of a modifier. If ever there was a time to ensure that you’re documenting defensibly, this would be it!  


And there you have it—five example scenarios that demonstrate when (and when not) to use a therapy assistant modifier. Hopefully these CQs and COs cause less of a fright when you see them from this point forward! Not sure if you need to apply a therapy assistant modifier to your service line? Drop a comment below, and we’ll do our best to sleuth out an answer for you.