Share This Post

CQ and CO Modifiers Part 2: Calculating the De Minimis to Support Modifier CO and CQ Claims Submission

June 25, 2021
Reimbursement By Deborah Alexander, Director

Welcome to Part 2 of our CQ and CO Modifiers 2022 Reimbursement Changes Series. In Part 1 we discussed the submission of the CQ and CO Modifiers that have been integrated into our documentation and staffing models since 2019.


2- Part CQ and CO Modifiers - Part 2


Beginning January 1, 2022, the increased risk when a provider comes under a payer documentation and Comprehensive Error Rate Testing (CERT) audit will increase simultaneously with the 15% financial reduction impact for services provided “in whole or in part” (De Minimis) by therapy assistants.

In Part 2, will review some of the recent treatment scenarios released by the Centers for Medicare and Medicaid Services (CMS) describing how to calculate the 15% payment differential when a physical therapy assistant (PTA) or certified occupational therapy (COTA) provides treatment.

In looking at the CMS examples that were recently released, remember that the rule of thumb for the highlighted scenarios include the CQ and CO modifier when the following occurs:

  1. PTA/COTA provides all the minutes independent of the PT/ OT.
  2. PTA/COTA provides a component of the services separately from the service that the PT and or OT provides, and it exceeds 10% of the total minutes for that service. The standard 10% (also known as the De Minimis standard) was finalized in CY 2020.
  3. Continue to report the CQ with the GP therapy modifier and the CO with the GO therapy modifier. Pair these correctly on the claims to avoid issues with processing.

It is important to note for the following examples, that services furnished by the PT together with the PTA or by the OT together with the COTA are serviced by the PT and/or the OTR.

Let’s Review Some CMS Examples

Patient Scenario #1:

  • The PTA provides: 23 minutes of 97110.
  • The PT provides: 13 minutes of 97110.
  • The PT provides 30 minutes on 97140.
  • Total treatment is 66 minutes or 4 units.

How would you bill? The total time for 97110 is 36 minutes or 2 units. Because at least 15 minutes were provided by the PTA, we know at least 1 unit of 97110 will require the CQ modifier.

Then, you must determine if the PTA serviced more than 10% of the remaining minutes. So, looking at the second unit of 97110- the PTA provided 8 minutes, the PT provided 13 minutes for a total of 21 minutes. If you want to determine the overall percentage, you must divide 8 into 21 which gives you .38 (multiply .38 x 100) which then equals 38 percent. Because 38 percent is higher than 10%, you can conclude, that the CQ modifier must be applied to the second unit for 97110. The two units of 97140 are furnished solely by the PT, so it will be billed as 2 units and does not require the CQ modifier.

Patient Scenario # 2:

  • The PTA provides 20 minutes of 97110.
  • The PT provides 15 minutes of 97110.
  • The PT also provides 23 minutes of 97140.
  • Total treatment is 58 minutes or 4 units.

How would you bill? The total time is 58 minutes or 4 units. Because the PTA performed a full 15 minutes of care (plus 5 minutes leftover), bill 1 unit of 97110 and include the CQ modifier. The PT provided 15 minutes of 97110 supporting one unit of 97110. These units for 97110 are reported as two separate line items on the claim form to distinguish the PT and PTA 97110 payment. One unit of 97140 can be submitted without the CQ modifier because the PT serviced a full 15 minutes (plus 8 minutes leftover).

Now, the million-dollar question, how do we submit the fourth unit? Because the remaining units are for two different CPT codes (97110 and 97140), we must compare the remaining units to determine which CPT code is appropriate to bill. The PTA has 5 minutes leftover of 97110 and the PT has 8 minutes leftover of 97140. Your next step is to determine which CPT code has the greater number of minutes and bill for that code. In this example, it would be 97140 as 8 minutes is greater than 5 minutes. So, another unit of 97140 for manual therapy would be billed without the CQ modifier as the PT serviced this task.

Patient Scenario # 3:

  • The OT provided 11 minutes of 97140.
  • The COTA provided 11 minutes of 97110.
  • Total treatment is 22 minutes or 2 units.

How would you bill this one? Here is an example where both CPT codes furnished the same number of minutes. The total is 22 minutes which only yields one unit of billable time. So, which do you bill, the 97140 or the 97110? Because the number of minutes is equal, either CPT code can be billed. One unit of 97140 delivered by the OT can be billed which would not require the CO modifier or one unit of 97110 could be billed which was delivered by the COTA and would require the CO modifier.

Patient Scenario # 4:

The next scenario from CMS is not a complex one, but it is important to point out minutes that may not be billable but still should be recorded. For example:

  • The PTA provided 5 minutes of 97110.
  • The PT provided 30 minutes of 97110.
  • Total treatment was 35 minutes or 2 units.

How would you bill this scenario? The PT would bill two units of 97110 which would not require the CQ modifier as the PT serviced 2 full 15-minute units. You still record the 5 minutes of 97110 furnished by the PTA even though it is not billable. The total treatment time and the documentation should reflect the PTA’s intervention regardless of the service being billable. This scenario highlights a compliance risk to ensure licensed providers document and apply their signature when services are provided, which most state licensing boards require.

Patient Scenario # 5:

Let us discuss a scenario highlighted by CMS which outlines services completed by the PTA independently and the PT and PTA together.

  • The PTA independently provides 3 minutes of 97110.
  • The PT and PTA together provide 27 minutes of 97110.
  • The total treatment was 30 minutes or 2 units.

Clearly, one unit of 97110 can be billed without the CQ modifier because a full 15 minutes was serviced by the PT and PTA together at the same time. The remaining 12 minutes of PT and PTA together time and the 3 minutes by the PTA are combined to determine how to bill the second unit. Take the PTA’s independent time of 3 minutes and divide that into total time of 15 minutes (PT and PTA time had 12 minutes remaining plus the 3 minutes solely delivered by the PTA) which results in 20%, exceeding the 10% CQ modifier requirement. At first glance, without doing the math, you may think 3 minutes would not equate to greater than 10%, but it certainly did in this case.

Patient Scenario # 6

A final example considers an untimed code for group therapy/97150.

  • The COTA provides 20 minutes of 97150, independent of the OTR.
  • The OTR provides 20 minutes of 97150 independent of the COTA.
  • Total time is 40 minutes of group therapy.

How do you think you would bill this one? Since the COTA provided more than 10%, the CO modifier would be applied to one unit of 97150.

To find the answers and review additional scenarios, read CMS’ billing examples and patient scenarios.

How Can LW Consulting, Inc. (LWCI) help you prepare for 2022?

Having an external review of your practice can help to minimize billing compliance risks. Having the documentation support the use of the CO and CQ modifier may likely become a payer audit target, no different than it currently is in the physician sector when services are provided by an NPP. Therapy providers need to ensure the documentation and staffing patterns support the CO and CQ modifiers billing compliance to minimize the risk of false claims.

Here are some ways that LWCI’s experts can help:

  • Conduct an external audit of your documentation when the CO and CQ modifier was applied.
  • Conduct an external audit of your claims submitted with the CO and CQ modifier to compare payers and staff schedules.
  • Conduct an assessment of your patient scheduling patterns for providing utilizing PTAs or OTAs.
  • Conduct a staffing assessment when considering expanding your practice.


For more information, contact Deb Alexander, Director, at 717-213-3122 or email

Contact Us