Let’s start with a typical scenario in physical therapy medical billing. Suppose you run a physical therapy practice. An established patient comes to you with chronic lower back pain. Even though the patient has surpassed the combined annual financial limit for therapies, you decide that therapeutic exercise and some manual therapy are medically necessary. So, you deliver the services. The session lasts 23 minutes, which is equal to 2 billable units, as per the 8-minute rule.
Everything goes well, and the billing department submits the claim. But to your surprise, the claim comes back denied. The reason? The biller didn’t use the KX modifier.
Billers make simple mistakes every day that end up in a denied claim. However, these mistakes are preventable if you know the latest physical therapy billing guidelines and requirements.
That is why we created this guide on physical therapy billing and coding. We will try to cover the latest changes in the billing guidelines and the best practices that you can follow to avoid costly denials. So, let’s start.
Physical Therapy CMS Billing Guidelines
Here are some things to keep in mind for 2026 physical therapy billing:
2026 Medicare Physician Fee Schedule Changes
In October 2025, the Centers for Medicare & Medicaid Services (CMS) finalized the Physician Fee Schedule (PFS) for 2026. As per this new PFS, qualifying Alternative Payment Model (APM), participants now receive a conversion factor of $33.5675, while non-qualifying participants, which is the category most outpatient physical therapy practices fall into, get a conversion factor of $33.4009.
This is a big increase of 3.77% and 3.26%, respectively. However, there is a catch. The entire increment is not transferred to the practices. CMS has now put an efficiency adjustment of -2.5% on the work RVUs of non-time-based codes. So, if we factor this in as well, then the net average reimbursement increase is only about 1.75%.
However, the good news is that in the new PFS, CMS has removed several therapy codes from the efficiency adjustment list. This includes frequently used codes like 97032, 97033, 97034, 97035, 97036, 97113, 97124, 97140, and 97533.
KX Modifier Threshold
As you might already know, CMS put an annual financial threshold on the combined physical and speech-language therapy services. If this dollar threshold is crossed, CMS asks billers to append modifier KX to the claims to indicate that even though the threshold is reached, the provided services are medically necessary.
For 2026 physical therapy billing, CMS has established this threshold at $2,480 for combined physical and speech-language therapy.
New Remote Therapeutic Monitoring (RTM) Codes
CMS finalized three new RTM codes for 2026: 98979, 98984, and 98985 as ‘sometimes therapy’ codes. These codes allow practices to bill for remote monitoring of a patient’s therapy progress between in-clinic visits, creating a new revenue stream for practices that can support compliant documentation.
All RTM codes require the appropriate therapy modifier (GP for physical therapy) and follow the same de minimis standard as in-clinic services when a physical therapy assistant (PTA) performs part of the service.
Common Challenges in Physical Therapy Billing
The following are the most common problems that billers face in physical therapy medical billing:
| Challenge | What It Means in Practice |
|---|---|
| 8-Minute Rule Miscalculation | Even one incorrectly rounded unit can prompt a denial, downcoding, or a post-payment audit. |
| Missing KX or CQ Modifiers | A missing modifier above the threshold, or on a PTA-furnished service, results in automatic claim rejection. |
| Prior Authorization Delays | Some insurance companies require prior approval for certain services. If billers fail to get this approval before providing the service, the claims will be rejected. |
| NCCI Bundling Edits | Codes like 97140 and 97530 cannot be billed together for the same region on the same day without modifier 59 and supporting documentation. |
| Documentation Gaps | Vague functional goals or notes that simply describe improvement without measurable details fail to support medical necessity. |
| Frequent Denials | Physical therapy carries an average denial rate of around 12.3%, well above the 5% to 8% range considered healthy for a practice. |
Best Practices to Streamline Physical Therapy Billing & Coding
Now that we have discussed the latest changes in physical therapy billing and the common problems that PT billers face, let’s discuss the best practices that can be implemented to avoid denials. Take a look:
Provide Detailed Documentation
First and foremost is documentation. This is the most important part of any medical claim. For physical therapy claims, you should provide the following with each claim:
- Plan of Care (POC): Must be established before treatment begins and certified with a physician or NPP signature.
- Progress Reports: Due at least once every 10 treatment visits or once every 30 calendar days, whichever comes first.
- Daily Treatment Notes: Must record the date of service, the specific time spent on each service, and the patient’s response.
- Functional Documentation: Notes should describe measurable functional deficits and how they affect activities of daily living.
Other Important Guidelines
- Make sure to check and keep track of the KX and CQ modifier thresholds for every patient. This should be done before providing the services, not after a claim is denied.
- Build NCCI edit checks directly into your claim scrubbing process.
- Eligibility verification and prior authorization are among the biggest causes of claim denials in physical therapy medical billing. So, verification and pre-authorization should be your first priority.
- Train your billing staff every quarter on the latest rules.
- Conduct internal coding audits on your highest-volume codes.
Final Thoughts
We have finally reached the end of this guide. Hopefully by now, you must have a good idea of the recent changes in physical therapy billing guidelines and how you can incorporate them. Before wrapping up, here is a quick recap of the essential points:
- On average, after all the adjustments, physical therapists can see an increase of 1.75% in reimbursements.
- KX modifier threshold for combined physical and speech-language therapy is $2,480.
- CMS has introduced new RMT codes.
However, even with all these guidelines in mind, billing can still be very frustrating, especially for small in-house billing teams. If you are looking for support, our physical therapy billing services are designed to help practices reduce denials.
