Editor’s note: The information here pertains to Medicare and CMS’s 2022 proposed rule, which is not finalized and subject to change before the end of 2021. The information here is current as of September 2021, and we will try to update information as it becomes available. For the most accurate information on the proposed rule, visit CMS’s proposed rule page.
November 2, 2021, update: CMS has released more information on the Final Rule. Learn the latest from their 2022 Fact Sheet.
Occupational and physical therapy organizations are required to report when an assistant (OTA or PTA) performs a service using the billing modifiers CO for OTAs and CQ for PTAs. Services with the assistant modifier will see a cost reduction in claim reimbursements beginning January 1, 2022.
These billing rules were originally proposed by the Centers for Medicare and Medicaid Services (CMS) in 2018. In 2020, organizations were required to begin reporting the assistant modifier when appropriate. And in 2022, organizations will begin to see a reduced reimbursement—as CMS puts it “85% of the otherwise applicable Part B payment”—for any CPT code line item containing the modifier CO or CQ.
CMS requires outpatient rehab clinics to use the CO and CQ modifier on any service that was “furnished in whole or in part by a PTA or OTA.” And “in part” was essentially defined as at least 10% of the service. The lack of clarity led to CMS developing the de minimis standard for determining if a service requires the modifier.
But, as is typical for CMS, it’s not that easy. The latest proposed rule for 2022 has more information on when to apply the modifier, and it gets a bit complicated. In our guide, we’ve broken down the new rules to help you better understand when to apply the modifier and how to improve Medicare billing compliance at your clinic.
A few important changes have happened since CMS’s 2021 proposed rule. Here are some of the most significant changes:
Finally, aside from the calculations needed to apply the assistant modifier, you will need to calculate whether or not the total number of timed service units would be constrained by the well-known CMS interpretation of the 8-minute rule. (That is, you are not allowed to bill for more than one timed unit of service for every 15 minutes spent providing timed services, rounded up to the nearest 15-minute increment.)
The de minimis standard considers any service in which more than 10% of the service was performed independently by an assistant must be reported with the assistant modifier.
Even though CMS has included de minimis calculations examples in the proposed rule, there is no need to go through those calculations when applying the assistant modifier on a line-item basis for timed services following the steps described above.
Additionally, CMS has clarified that any service performed by both a therapist and assistant in tandem (at the same time to the same patient) will not require the assistant modifier.
CMS provided six CO/CQ modifier examples in their proposed rule (pg. 287-288), which we’ve included below.
A PTA provided 10 mins of therapeutic exercise (97110) before the PT came in and provided the remaining 5 mins of therapeutic exercise to the patient. In total, the patient received 15 mins of therapeutic exercise, which qualifies for a single unit.
Answer: Bill one unit of 97110 with the CQ modifier.
A PTA provided 5 mins of therapeutic exercise (97110) to a patient, followed by the PT providing another 6 mins of therapeutic exercise. In total, the patient received 11 mins of exercise, which qualifies for a single unit (between 8-22 mins).
A PTA provided 22 mins of therapeutic exercise (97110) to a patient. The PT continued the exercise for another 23 mins. In total, the patient received 45 mins of therapeutic exercise, which qualifies for 3 units.
Answer: Bill one unit of 97110 with the CQ modifier, and two units of 97110 without the modifier.
A PT provided 12 mins of therapeutic exercise (97110) before handing off the patient to the PTA for 14 more mins of therapeutic exercise. After the exercises, the PT returns and provided 20 mins of hands on therapy (97140). In total, the patient received 46 mins of service, which qualifies for 3 units.
Answer: Bill one unit of 97140 without the modifier, one unit of 97110 with the CQ modifier, and the final unit of 97110 without the modifier.
An OTA provided 11 mins of home management training (97535) to a patient. Then, the OT takes over and provided 11 mins of therapeutic activities (97530) to the patient. In total, the patient provided 22 mins of service, which qualifies for a single unit.
Answer: Bill one unit of 97535 with the CO modifier, or bill one unit of 97530 without the modifier. Preferentially, we suggest the ladder.
An OTA provided 20 mins of group therapy (97150) for some patients. After the OTA finishes, the OT provided another 20 mins of group therapy. In total, the 40 min session counts for a single unit as 97150 is an untimed code.
Answer: Bill one unit of 97150 with the CO modifier.
CMS is never shy about creating rules, so there are a few different aspects about the assistant modifier rule that you should keep in mind. Here are some of those rules, and other common questions about the assistant modifier.
When billing for Medicare Part B reimbursements, yes, the modifier is necessary when applicable. However, other private or commercial payers have different billing requirements and may not require the assistant modifier or may use a different modifier altogether. Our guide only pertains to the rules set for Medicare Part B billing.
The assistant modifiers are required for all outpatient services, including private practice, physician offices, rehab agencies, CORFs, SNF Part B, HHA Part B, and hospital outpatient departments. The rule does not apply to Critical Access Hospitals, which are paid differently.
If a therapist and assistant co-treat a patient—in other words, provide a service at the same time to the same patient—you are not required to report the modifier.
No, services performed by a PT aide are not billable to Medicare. Thus, the assistant modifier rule isn’t applicable.
No, services should not be split onto separate line items for a single unit. However, if a therapist and assistant both independently provided a service to a patient that equals two units, then you can bill one line item with the modifier and one without. To clarify, here’s an example:
A PT provides therapeutic exercise to a patient for 15 mins (CPT code: 97110). After one round, the therapist passes the patient off to the assistant to perform another round of therapeutic exercises for 15 mins. Overall, the patient received 30 mins of exercise, or two units of 97110. When billing, the clinic can bill 97110 once without the modifier, and a second time with the CQ modifier to designate the assistant’s service.
When documenting, the CO and CQ modifiers do not need any additional explanations. However, CMS always suggests maintaining defensible documentation to support your billing choices.
To help with your clinic’s billing compliance, Clinicient’s Insight system will automatically apply the assistant modifier to applicable claims. Billing administrators can review claims before they’re submitted to Medicare to ensure the modifier is applicable.
If you want to learn more about the rule, turn to the Centers for Medicare and Medicaid Services (CMS) for more information. You can also read the entire proposed rule on the Federal Register.