By MEDCLAIM Services editorial team · Published · 2 min read
Physical, occupational and speech therapy are billed in time units, and small counting errors repeat on every visit in a course of care. The rule Medicare uses to turn minutes into units, usually called the 8-minute rule, is simple once it is laid out, but it is often applied the wrong way.
Total minutes, not minutes per code
When a patient receives more than one timed service in a day, Medicare adds up the minutes of all the timed services and uses that total to decide how many units can be billed. The units are then assigned to the individual codes.
This is where practices go wrong. Counting each code on its own can produce more units than the total supports, or fewer. The total comes first.
The unit table
Under Medicare's method, a total of 8 to 22 timed minutes supports 1 unit, 23 to 37 minutes supports 2 units, and 38 to 52 minutes supports 3 units. The pattern continues: 53 to 67 minutes supports 4 units and 68 to 82 minutes supports 5.
A worked example
Say a visit includes 24 minutes of therapeutic exercise and 10 minutes of manual therapy, both timed codes. Counted separately, it is tempting to bill two units of exercise and one of manual therapy. Counted the Medicare way, the total is 34 minutes, which supports 2 units for the visit, and the note has to show how those 2 units are split between the codes.
When two services each run only a few minutes but together reach a unit, Medicare gives that unit to the service with the most minutes.
Untimed services are separate
Evaluations and re-evaluations are not timed codes. They are billed as one unit for the service and do not enter the minute count for timed codes.
Modifiers every Medicare therapy line needs
Each therapy line on a Medicare claim carries a modifier showing which discipline's plan of care it belongs to: GP marks physical therapy, GO occupational therapy and GN speech-language pathology. When a physical therapist assistant provides all or part of a service, the line also needs the CQ modifier, which Medicare pays at a reduced rate.
Commercial payers
Not every payer counts the Medicare way. Some commercial plans count each timed code separately instead of totaling the minutes, so the same visit can support a different number of units depending on the payer. The rule for each payer belongs in its billing setup, not in the therapist's memory.
The takeaway
Document start and stop times or total minutes for every timed service, total them before choosing units, and set each payer's counting method once. Done consistently, the 8-minute rule stops being a source of denials and audit findings.
Official sources: CMS Claims Processing Manual, chapter 5 (outpatient therapy) (external site), CMS coverage database: article A56566 (outpatient therapy) (external site)
This article is general information, not legal or billing advice for a specific practice. Payer and program rules change, so check the linked official sources for the current version.