Humans are naturally social creatures. Being in groups gives us more confidence—and for patients seeking rehab therapy services, that can often lead to better outcomes. But, as a therapist, knowing when and how to bill for one-on-one services (a.k.a. individual therapy) in a group treatment setting can be tricky to say the least. Here are a few things to consider when treating multiple patients during the same timeframe:

Billing for Individual Services

In some ways, billing for one-on-one therapy in a group setting seems illogical; I mean, c’mon—can you really provide individualized care within a group setting? While the terminology doesn’t seem to jibe, in reality, it’s a fairly common therapy practice—which is why it’s important for therapists to know how to bill for it appropriately. So, here’s the deal: CMS allows direct one-on-one minutes to “occur continuously (15 minutes straight), or in notable episodes (for example, 10 minutes now, 5 minutes later)”—even if, in between those episodes, the therapist provides group instruction or performs one-on-one treatment with other individuals in the group. However, each individual therapy service “should be of a sufficient length of time to provide the appropriate skilled treatment in accordance with each patient’s plan of care.”

Knowing When One-On-One Billing Isn’t Appropriate

Of course, it’s also important to know when billing for one-on-one services is not appropriate. Let’s look at an example, as adapted from this APTA resource: four patients—each diagnosed with arthritis—are all scheduled to see their physical therapist at the same time. Because each patient suffers from the same condition, the PT performs a total of 55 minutes of group exercise concurrently with all four patients, including a five-minute rest period after the first 20 minutes of exercise. At the end of the session, the therapist reminds the patients to continue with their home exercise programs as prescribed. In this instance, the group has a common unifying condition (arthritis), and the patients aren’t ever treated on a one-on-one basis. Thus, it would be appropriate to bill group therapy (97150) for each of the four patients.

Applying the 8-Minute Rule

Now that you know when not to bill for one-on-one treatment, here’s an example of when it’s appropriate. Remember, when you’re billing for timed one-on-one services, you must follow the 8-Minute Rule. Here’s how CMS explains it: You have three patients—let’s call them Chico, Harpo, and Groucho—over a 45-minute period. Each patient receives eight minutes of direct one-on-one contact with you for the first 24 minutes. Then, you work directly with Chico for an additional 10 minutes, Harpo for five minutes, and Groucho for six minutes. So, the total amount of direct one-on-one time for each patient is:

  • 18 minutes with Chico
  • 13 minutes with Harpo
  • 14 minutes with Groucho

Thus, you’re allowed to bill each Marx brother—er, patient—for one unit of 97110 (therapeutic exercise). But, because it’s group therapy, you couldn’t bill each patient for three units of 97110.

Using Modifier 59

Finally, when billing one-on-one codes, you should never include a time-based procedure or another constant-attendance modality for the same 15-minute period. Phew, that’s a mouthful, huh? But, to complicate your life just a bit more, that doesn’t preclude you from billing for both group therapy and individual therapy on the same day—as long as:

  1. the group session is clearly distinct or independent from the individual services you provide, and
  2. you apply modifier 59.

It’s your responsibility to determine whether you’re providing linked services or wholly separate services. When the former applies—and the group therapy code forms an edit pair with the one-on-one service code—you can ensure payment for both services by affixing modifier 59 to the appropriate code (check out the chart on this page to determine which code requires the modifier).


Billing for physical therapy services—especially those provided in a group setting—can be tricky. Luckily, you don’t have to go it alone. There’s a wealth of resources (including this blog post) at your disposal. What remaining questions do you have about billing for one-on-one services in a group treatment scenario? Do any issues keep popping up for you? Tell us your thoughts in the comment section below.