Physical therapy coding requires time-based procedure codes, functional outcome documentation, and therapy cap awareness. This page covers the top ICD-10-CM diagnosis codes and CPT therapy procedure codes used by physical therapists and physical therapy practices across the United States.
Therapeutic exercise (97110) and therapeutic activities (97530) are time-based — bill in 15-minute units and document the total time spent in timed vs. untimed services.
Always document functional limitations and measurable goals to support medical necessity for ongoing PT beyond 8–12 visits.
Use KX modifier when therapy services exceed the annual Medicare cap but are medically necessary — document this in the plan of care.
97012 (mechanical traction) and 97014 (electrical stimulation) are constant attendance codes only; supervised (non-attended) versions may not be separately billed in all payer contracts.
97110 (Therapeutic exercise) and 97530 (Therapeutic activities) are the most frequently billed PT codes. Both are time-based: bill one unit per 15 minutes of direct one-on-one treatment. Document start/stop times for each timed code.
What is the 8-minute rule?
Under Medicare, a single 15-minute timed unit requires at least 8 minutes of treatment. For multiple timed units, total treatment time determines the number of billable units — use the total-time method (not the individual-service method) per CMS policy.
When is the KX modifier required?
The KX modifier is required on PT claims after the annual therapy cap is exceeded (typically ~,230 for PT/SLP combined under Medicare). It attests that services are medically necessary and documented in the plan of care.
What ICD-10 code is used for post-op PT after knee replacement?
Z47.1 (Aftercare following joint replacement surgery) is the primary code for post-surgical PT. Add the condition treated (M17.11) as a secondary code. Z47.1 covers PT, OT, and wound care following joint replacement.
How does OmniMD support physical therapy billing?
OmniMD’s Physical Therapy EHR module includes timed code calculators, therapy cap tracking with KX modifier alerts, functional outcome measure tools (FOTO, OPTIMAL), and progress note templates aligned with Medicare documentation requirements.
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