CPT 97110 Therapeutic Exercise: Billing Rules, Documentation, and Common Denials

What CPT 97110 covers

97110 is therapeutic exercise: exercises to develop strength and endurance, range of motion, and flexibility, for one or more areas. It is a timed code billed in 15-minute units, and it requires direct, one-on-one contact between the patient and the therapist or assistant.

Both physical and occupational therapists bill 97110. On Medicare claims, it must carry the discipline modifier for the plan of care it falls under: GP for physical therapy, GO for occupational therapy.

How units are counted

For Medicare and payers that follow CMS, units come from the 8-minute rule: add up the total minutes of all timed codes for the visit, then convert to units. 8 to 22 minutes is one unit, 23 to 37 is two, and so on. The minutes for each code decide how the units are split between codes.

Some commercial payers use the substantial-portion method instead, which counts each code on its own. Know which method each of your payers uses — billing the wrong way is one of the quietest ways to under- or over-bill.

What to document

Payers look for the same things when they review 97110:

• Total timed minutes and minutes for each timed code.
• The specific exercises, with parameters (sets, reps, resistance, positions).
• Why the exercise needed the skill of a therapist — progression, cueing, or modification — not just supervision.
• How the exercise ties back to the functional goals in the plan of care.

Why 97110 gets denied

• Exercise that looks like a home program — repetitive work with no skilled input documented.
• Units that don't match documented minutes.
• Missing or wrong GP/GO modifier, or the KX modifier left off after the Medicare threshold.
• Group sessions billed as 97110 when they should be 97150.
• Treatment outside a certified plan of care.

97110 vs 97530

97110 targets a specific impairment — strength, motion, flexibility. 97530 uses dynamic, functional activities to improve performance in tasks like lifting, transfers, or reaching. If the note describes a functional task, 97530 is usually the better fit. Billing the same activity as both is a red flag for auditors.