Understanding occupational therapy billing units

Some occupational therapy CPT codes are service-based, “untimed” codes. When using these codes, regardless of how much time you spend with a patient providing service, you can only bill code per day. Other codes are time-based — such as therapeutic exercise (97110) and manual therapy (97140). With these codes, you bill “units” of time. In this post, we’ll explain how occupational therapy billing units work so you can receive accurate reimbursements from Medicare.

How occupational therapy billing units work

For services billed via time-based CPT codes, you’ll bill one unit for every 15 minutes of service. While the units of time are measured in 15-minute increments, billing units aren’t as straightforward as they seem. Not all services that are time-based can easily be divided into 15-minute increments. For example, if you spend 40 minutes on manual therapy, would you bill two 15-minute units or three?

The Medicare 8-Minute rule

First, you need to understand what’s often to as the “8-Minute Rule.” Medicare answers the question of how many units to bill by saying that a service must be provided for a minimum of 8 minutes in order to bill one unit. If a treatment required up to 22 minutes, you’d still bill one unit, however. You can’t bill two units until the clock runs to 23 minutes.

Here’s the exact wording of the rule: “When only one service is provided in a day, providers should not bill for services performed for less than 8 minutes. For any single timed CPT code in the same day measured in 15-minute units, providers bill a single 15-minute unit for treatment greater than or equal to 8 minutes through and including 22 minutes. If the duration of a single modality or procedure in a day is greater than or equal to 23 minutes through and including 37 minutes, then 2 units should be billed.”

The Centers for Medicare & Medicaid Services (CMS) also provides a reference resource to help you see at a glance how many units you should bill for a timed service:

Service time	Number of billing units
0 -7 minutes	0 units
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 – 97 minutes	6 units
98 – 112 minutes	7 units
113 – 127 minutes	8 units

How to handle multiple treatments in one day

The chart is helpful if you’re only billing a single time-based CPT code, however many units you bill. But what should you do if more than one time-based treatment is provided in a day?

Multiple short treatments

First, let’s address a situation where you’re providing more than one timed treatment, but each treatment is less than 8 minutes. In this case, the guidelines dictate that you bill one unit for the CPT code of the treatment you spent the most time on:

“If any 15-minute timed service that is performed for 7 minutes or less than 7 minutes on the same day as another 15-minute timed service that was also performed for 7 minutes or less and the total time of the two is 8 minutes or greater than 8 minutes, then bill one unit for the service performed for the most minutes. This is correct because the total time is greater than the minimum time for one unit. The same logic is applied when three or more different services are provided for 7 minutes or less than 7 minutes.”

Multiple treatments of at least 8 minutes

Next, let’s look at a situation where you’re providing more than one service in a day and each goes over the 8-minute mark. For this situation, CMS guidelines say that all the time for timed treatments should be combined and then billed based on the combined time.

The guidelines state, “If more than one 15-minute timed CPT code is billed during a single calendar day, then the total number of timed units that can be billed is constrained by the total treatment minutes for that day.”

Here’s an example offered to illustrate how this works.

If you performed 24 minutes of neuromuscular reeducation (code 97112) and 23 minutes of therapeutic exercise (code 97110), you would add 24 and 23 to get 47. If you look at the chart above, 47 total minutes should be billed as 3 units, so you would bill 2 units for code 97112 (since it was performed for a longer amount of time) and 1 unit for code 97110.

Other considerations

So far, the rules we’ve been discussing apply only to Medicare and Medicaid billing. What about if you’re billing private payors? And what about assessment and management time? Let’s look at each of these questions.

When billing private payors

Most private payors have adopted some version of the 8-Minute Rule, but not all have. Typically, those who do use a version of the 8-Minute Rule don’t allow for time to be combined for multiple treatments, however. In these cases, you should bill each treatment code the appropriate number of units for the time you spent on that treatment alone. But not all insurers use the 8-Minute Rule, so you’ll want to look at the guidelines for each client’s insurer to make sure you’re billing timed units correctly.

Billing for assessment and management time

It’s important to know that you can include time spent on assessment and management, as long as this time was spent with the patient and it’s well-documented. You’ll want to be sure you can defend your decision to bill for the time if you’re questioned on it, but it’s fully allowable.

The easiest way to determine how to bill units for timed codes is to remember the 8-Minute Rule and to keep the reference chart above handy. With the reference chart, you won’t need to worry about dividing by 15 and dealing with remainders — you can simply refer to the chart to see which unit category the total minute count falls into.