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One-on-One Services vs. Group Services

If considering one-on-one services vs. group services, we’ve got the rules you need to avoid confusion and bill for the correct services.

Melissa Hughes
5 min read
June 29, 2023
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Figuring out how to bill for one-on-one services vs. group services for therapy can be tricky—so tricky that you may need a bit of post-billing therapy yourself. But if there’s one thing that’s clear, it’s that you should never bill one-on-one CPT codes if you’ve provided group therapy services, as doing so increases your risk of a Medicare audit. 

So what, exactly, are you allowed to bill (and when)? How do you even know if you’ve provided one-on-one or group therapy? Why is Medicare so complicated, and private insurance carriers even more so? While we don’t have the answer to that last question (sorry!), we can certainly touch on the first two. Let’s begin!

What’s the difference between one-on-one services vs. group services, exactly?

One-on-one services—a.k.a. individual therapy—are defined by direct one-on-one patient contact. Direct patient contact is a concept that’s mostly determined by the American Medical Association (AMA)—the organization that establishes and edits CPT codes. So every time a code calls for direct patient contact (or one-on-one services), it requires “face-to-face” time. To add a little more context, the Medicare program requires that direct patient contact either occurs “continuously (15 minutes straight), or in notable episodes (for example, 10 minutes now, 5 minutes later).” The AMA refers to this as intermittent one-on-one.

So, if you bill using one-on-one codes, you’re telling that payer (whether it’s Medicare or a commercial plan) you definitely had one-on-one contact with that patient. Additionally, one-on-one CPT codes are cumulative, require constant attendance, and are time-based—which means they fall under the 8-minute rule (or the AMA rule of eights). Here’s a breakdown of how many single units you can bill based on the total time of treatment under the 8-minute rule:

  • 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

A Big Disclaimer

Many rehab therapists believe that Medicare handles one-on-one billing differently than other payers. This isn’t the case! Because one-on-one time is defined by the AMA in the CPT code definitions, all payers adhere to the same rules. That means you can’t double-bill one-on-one time just because you’re seeing patients from different payers. The exception, of course, would be if you’re working with therapy assistants, techs, or extenders within the constraints of your state practice act. 

What are group therapy services?

According to CMS, “Group therapy consists of simultaneous treatment to two or more patients who may or may not be doing the same activities. If the therapist is dividing attention among the patients, providing only brief, intermittent personal contact, or giving the same instructions to two or more patients at the same time, it is appropriate to bill each patient one unit of group therapy.” As the APTA explains it, that means the “therapist involved in group therapy services must be in constant attendance, but one-on-one patient contact is not required.”  

For example, let’s say you have two patients present for treatment at 10 AM. Mrs. Smith has a frozen shoulder and Mr. Jones has a knee extension lag following a knee replacement. You begin treatment by spending six minutes with Mrs. Smith, then spend seven minutes with Mr. Jones, going back and forth and spending about equal time with each patient until 10:54 AM. At 10:54, you have both patients do return demos of their home exercise programs for seven minutes. Because the total one-on-one time was 54 minutes for the two patients, each can be billed for two units of one-on-one and each could be billed for one unit of group code. 

Keep in mind that one-on-one time does not have to be continuous and can be delivered intermittently. The AMA defines on-on-one time as, “The work of the physician or other qualified healthcare professional consists of face-to-face time with the patient (or caregiver, if applicable) delivering skilled services. For the purposes of determining the total time of a service, intermittent intervals of treatment at the same visit can be accumulated.”

If you’re looking for more group therapy examples, the APTA offers this detailed resource with multiple scenarios for both PTs and PTAs.

Can therapists bill for one-on-one services while treating multiple patients?

Even if you’re working with more than one person, it is possible to bill for one-on-one services if you follow the guidelines in Medicare’s above-listed definition of one-on-one time. However, each individual therapy episode “should be of a sufficient length of time to provide the appropriate skilled treatment in accordance with each patient’s plan of care.” Here’s an example of a billing scenario, as adapted from this APTA resource:

Let’s say you work with three patients—for the sake of this post, we’ll call them Moe, Larry, and Curly—over one 45-minute period. Each patient receives 8 minutes of direct one-on-one contact with you for the first 24 minutes. Then, you work directly with Moe for an additional 10 minutes, Larry for 5 minutes, and Curly for 6 minutes. So, the total amount of direct one-on-one time for each patient is:

  • Moe: 18 minutes
  • Larry: 13 minutes
  • Curly: 14 minutes

Thus, you’re allowed to bill each stooge—er, patient—for one unit of 97110 (therapeutic exercise).

Do the rules change if I’m billing multiple payers?

Okay, we know, we know—we already addressed this. But this question crops up enough that we really want to hammer down this answer. Major billing experts agree that therapists should not bill one-on-one codes with other time-based procedures or constant attendance modalities that occur during the same 15-minute period. (No double-billing, y’all!)

To be clear, that doesn’t preclude you from billing for both group therapy and individual therapy on the same day—so long as the group session is clearly distinct or independent from the individual services and you use modifier 59. (For more information, check out this modifier 59 post.)

Hopefully, this post answered at least a few of your questions about one-on-one services and group services, but as we know, Medicare is complicated, and these are just the basics. For more details, refer to our guides to the 8-minute rule, CPT codes, and Medicare. And if you’re new to billing altogether, take a look at our guide to private practice billing.


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