- Key Takeaways
- CPT code 97110 reports therapeutic exercise to build strength, endurance, range of motion, or flexibility, delivered one-on-one and billed in timed 15-minute units.
- To be payable, 97110 must require the skill of a therapist; a self-directed home exercise program that needs no clinical judgment is not billable.
- Under the CMS 8-Minute Rule, at least 8 minutes of a timed service supports one unit, and billable units follow the total timed minutes of the session.
- Many commercial payers instead use the AMA Rule of Eights, counting each timed service separately, so the same session can yield a different unit total by payer.
- Medicare claims need the GP therapy modifier, the KX modifier above the annual therapy threshold, and the CQ modifier when a physical therapist assistant provides the service.
An Office of Inspector General audit of outpatient physical therapy found that 61 percent of the Medicare claims it reviewed did not meet requirements for medical necessity, coding, or documentation, and estimated Medicare overpaid about $367 million for non-compliant outpatient therapy in a single six-month period. Therapeutic exercise, CPT code 97110, sits at the center of that finding. It is the most frequently billed physical therapy code, and its denials almost always trace back to one thing: a note that does not prove the service required a therapist’s skill.
Current as of 2026. Always verify code status and payment with your specific payer, since policies change.
What 97110 is: therapeutic exercise, one-on-one and timed
97110 reports therapeutic exercise performed to develop strength, endurance, range of motion, or flexibility, for one or more body areas. It is a direct, one-on-one service, meaning the provider is in constant attendance with the patient, and it is a timed code billed in 15-minute units. It is billed by physical therapists, occupational therapists, and, within their scope, chiropractors and other qualified providers.
The clinical picture is familiar: a patient recovering from a knee replacement doing progressive strengthening, or a post-stroke patient working on range of motion. What separates a payable 97110 from a denied one is not the exercise itself. It is whether the record shows the exercise needed a licensed therapist to deliver it.
The real test: is it skilled care?
This is the heart of 97110, and it is where the OIG findings land. For therapeutic exercise to be billable, it has to require the skills and knowledge of a therapist: to establish or progress the program, to correct technique, to ensure safety, and to apply clinical judgment as the patient responds. A set of exercises a patient can safely perform on their own, without a therapist’s ongoing involvement, is a home exercise program, and it is not separately billable as 97110.
So the note has to answer a specific question a reviewer will ask: why did this require you? Documentation that shows progression decisions, real-time adjustments, safety monitoring, and clinical reasoning supports the code. Documentation that reads like a generic exercise handout, with no evidence of skilled involvement, is the single most common reason 97110 is denied or recouped. Getting this right is less about the code and more about how therapists are trained to write the note.
Counting units: the 8-Minute Rule, and where commercial payers differ
97110 is timed, so the number of units depends on minutes, and this is where multi-payer practices get tripped up.
Under Medicare’s 8-Minute Rule, you need at least 8 minutes of a timed service to bill one unit, and total billable units are set by the total timed minutes across the whole session, not by each service calculated separately:
- 8 to 22 minutes: 1 unit
- 23 to 37 minutes: 2 units
- 38 to 52 minutes: 3 units
- 53 to 67 minutes: 4 units
Here is the part competitors skip. Many commercial payers do not use the CMS method. They use the AMA’s Rule of Eights, which evaluates each timed service on its own against the 8-minute threshold rather than totaling the session. The same 45-minute visit can therefore produce a different unit count depending on whether the payer follows CMS or AMA rules. Billing every payer as if it were Medicare is a quiet, recurring source of denials and underbilling. Our physical therapy billing guide works through the unit math in full, including mixed-service sessions.
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Documentation requirements for 97110
A defensible 97110 note should include:
- A plan of care with the diagnosis, functional goals, and frequency and duration
- The specific exercises performed, the body parts treated, and parameters such as sets and repetitions
- Objective measures and documented progress toward the goals
- A clear rationale showing why the service required a therapist’s skill
- The total timed minutes supporting the units billed
The through-line is skilled care plus time. Miss either and the claim is exposed.
Modifiers that matter for 97110
- GP: indicates the service was delivered under a physical therapy plan of care. Required on Medicare claims (GO for occupational therapy, GN for speech).
- KX: added when the patient exceeds the annual therapy threshold and continued care is medically necessary. Without it, claims above the threshold deny.
- CQ: indicates the service was furnished in whole or part by a physical therapist assistant, which carries a payment reduction (CO for occupational therapy assistants).
- 59 or an X modifier: used when 97110 is billed with a code it is bundled against under NCCI, most commonly 97140 manual therapy, to show the services were distinct.
Common billing errors to avoid
- Billing 97110 for unskilled exercise. If the note does not show skilled involvement, it reads as a home program and denies.
- Applying Medicare’s 8-Minute Rule to every payer. Confirm whether each commercial plan uses CMS rules or the Rule of Eights.
- Miscounting mixed-service sessions. Total timed minutes drive Medicare units, not each service calculated alone.
- Omitting required modifiers. Missing GP, KX above the threshold, or the assistant modifier causes denials or overpayments.
- Billing 97110 and 97140 without a distinct-service modifier and supporting documentation.
- Counting non-treatment time. Only direct, one-on-one timed minutes count toward the units.
Related codes and comparisons
- 97110 vs 97530 (therapeutic activities): 97110 targets a single parameter such as strength or range of motion through exercise; 97530 involves dynamic, multi-parameter functional activities like lifting or reaching. Both are timed.
- 97110 vs 97112 (neuromuscular reeducation): 97112 addresses movement, balance, coordination, and proprioception, a different clinical purpose from strengthening or range of motion.
- 97140 (manual therapy): frequently performed in the same session as 97110 and subject to an NCCI edit, so it needs a distinct-service modifier when both are billed.
Reimbursement context
97110 is paid per unit under the Medicare Physician Fee Schedule, so total payment scales with the units supported by the session. Two adjustments matter: the Multiple Procedure Payment Reduction reduces the practice-expense portion on additional therapy units the same day, and the assistant modifier reduces payment when a PTA or OTA delivers the service. Note also that 97110 is not on Medicare’s permanent telehealth list, so in-person and telehealth coverage can differ. Treat any single figure as illustrative and confirm current rates and threshold amounts through the CMS Physician Fee Schedule Look-Up Tool, which updates annually.
The bottom line
97110 is the workhorse of rehab billing, and the OIG has made clear it is also a compliance focus. The claim is not won by the exercise, it is won by the note: prove the service required a therapist’s skill, count the units by the correct payer’s rule, and apply the right modifiers. For practices that would rather not track therapy thresholds, assistant modifiers, and payer-specific unit rules claim by claim, Neolytix has supported healthcare organizations across the United States for over 14 years, with rehab therapy coding review built into its medical billing services so therapeutic exercise claims hold up before they go out.
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This guide reflects Neolytix’s expertise in healthcare revenue cycle management and is intended for educational purposes only. It does not constitute legal or compliance advice. CPT codes and reimbursement rates are periodically updated by the AMA and CMS.
Sources
- Office of Inspector General, U.S. Department of Health and Human Services. Many Medicare Claims for Outpatient Physical Therapy Services Did Not Comply With Medicare Requirements (A-05-14-00041). https://oig.hhs.gov/oas/reports/region5/51400041.pdf
- American Medical Association. CPT therapeutic procedures codes (97110). https://www.ama-assn.org/practice-management/cpt
- Centers for Medicare & Medicaid Services. Therapy services and the 8-Minute Rule guidance. https://www.cms.gov/medicare/billing/therapy-services
- Centers for Medicare & Medicaid Services. Physician Fee Schedule Look-Up Tool. https://www.cms.gov/medicare/physician-fee-schedule/search
- AAPC. CPT code 97110 reference. https://www.aapc.com/codes/cpt-codes/97110
Frequently Asked Questions
How many units of 97110 can you bill?
There is no fixed cap on 97110 units; the number follows total timed treatment minutes under the payer’s counting rule. Under Medicare’s 8-Minute Rule, 8 to 22 minutes supports one unit, 23 to 37 supports two, and so on. Units must reflect direct one-on-one time and be supported by documentation.
What is the 8-minute rule for 97110?
The 8-Minute Rule is how Medicare converts timed treatment minutes into billable units. You need at least 8 minutes of a timed service to bill one unit, then roughly each additional 15 minutes adds a unit. For a session with several timed services, Medicare totals all timed minutes to set the units.
What is the difference between 97110 and 97530?
97110, therapeutic exercise, targets a single parameter such as strength, range of motion, endurance, or flexibility. 97530, therapeutic activities, involves dynamic, multi-parameter functional tasks like lifting or reaching. Both are timed. Billing them on the same day requires documentation showing distinct interventions and, for many payers, a distinct-service modifier.
Can 97110 and 97140 be billed together?
Yes, when both are separately performed and documented. 97110 (therapeutic exercise) and 97140 (manual therapy) are subject to an NCCI edit, so many payers require a distinct-procedural-service modifier (59 or an X modifier) on the appropriate code, with documentation showing the services were separate. Without it, one code may be denied.
What documentation is required for 97110?
Payers expect a plan of care with the diagnosis and goals, the specific exercises performed with body parts and parameters, objective measures and progress, the total timed minutes, and a clear rationale showing the service required a therapist’s skill. Notes that read like a self-directed home program are the leading cause of 97110 denials.
