Physical therapists (PTs), physical therapist assistants (PTAs), occupational therapists (OTs), occupational therapy assistants (OTAs) and speech-language pathologists (SLPs) have CPT codes which describe the interventions they provide that are time-based and service-based (untimed). A question I often receive is how much time must I spend providing an intervention that is service-based (untimed) in order to be able to bill for that CPT code to any insurance carrier, including the Medicare program? In this article, I will answer this question. QuestionHow much time must I spend providing an intervention that is service-based (untimed) in order to be able to bill for