If a claim is denied, the cause is usually one of three things: the wrong CPT code, a missing or misused modifier, or a documentation gap that does not match what was billed.
When you know which codes need modifiers and where denials commonly happen, you can catch billing issues before they slow down payment. This guide walks through the CPT codes physical therapy practices commonly used in 2026, the modifiers that affect payment, and the denial issues to watch for.
PT CPT codes identify the specific service a therapist provides during a patient visit, such as an evaluation, therapeutic exercise, manual therapy, or neuromuscular re-education.
CPT codes work alongside other codes on the claim:
A typical physical therapy claim includes the appropriate CPT or HCPCS code, diagnosis code, and any required modifier. The codes should match the service documented in the patient’s record and support the medical necessity of the treatment.
For example, 97110 identifies therapeutic exercise, while the ICD-10-CM code explains the condition being treated. A modifier may provide additional information about how, where, or by whom the service was provided.
The most common CPT for physical therapy fall into two broad groups: evaluation codes and treatment codes. Evaluation codes describe the assessment of a patient, while treatment codes describe the therapy performed during the visit.
These are the common cpt codes used in physical therapy:
CPT Code | Description | Timed or Untimed |
97161 | Physical therapy evaluation, low complexity | Untimed |
97162 | Physical therapy evaluation, moderate complexity | Untimed |
97163 | Physical therapy evaluation, high complexity | Untimed |
97164 | Physical therapy re-evaluation | Untimed |
97110 | Therapeutic exercises to develop strength, endurance, range of motion, and flexibility | Timed |
97112 | Neuromuscular re-education | Timed |
97113 | Aquatic therapy with therapeutic exercises | Timed |
97116 | Gait training, including stair climbing | Timed |
97124 | Massage therapy | Timed |
97140 | Manual therapy techniques | Timed |
97150 | Therapeutic procedure(s), group | Untimed |
97530 | Therapeutic activities | Timed |
97535 | Self-care and home management training | Timed |
97032 | Electrical stimulation, manual, each 15 minutes | Timed |
97035 | Ultrasound, each 15 minutes | Timed |
For 97161–97163, the evaluation level depends on the documented complexity of the patient’s history, examination, clinical presentation, and clinical decision-making. The code does not depend simply on how long the evaluation takes.
97164 is different from a routine progress assessment. Use it when the documentation supports a separate re-evaluation of an established plan of care, such as when the patient’s condition or functional status changes or the treatment plan needs modification.
The treatment codes above describe the specific intervention provided. For example, 97110 reports therapeutic exercise, 97140 reports manual therapy, and 97530 reports therapeutic activities. The clinical note should support the service reported and the treatment time for timed codes.
Medicare’s 8-minute rule helps determine how many 15-minute units you can bill for timed therapy codes based on the total timed treatment minutes documented for the visit.
Total Minutes | Units You Can Bill |
8–22 minutes | 1 unit |
23–37 minutes | 2 units |
38–52 minutes | 3 units |
53–67 minutes | 4 units |
For example, a therapist provides 12 minutes of 97110 and 12 minutes of 97140. The total is 24 timed minutes, so the visit supports 2 units.
Remember: This rule applies to Medicare timed therapy services. The evaluation codes listed above are untimed and do not use this unit calculation.
Physical therapy modality codes differ based on how the service is provided and how Medicare pays for it.
Important: Commercial payer rules can differ, so verify the applicable payer policy before billing a modality separately.
NCCI edits may bundle certain CPT code pairs. You can report both services when the current NCCI edit allows separate reporting and the documentation supports that the services were distinct.
Code Pair | Key Check |
97140 + 97530 | Verify the current NCCI edit and document separate services and treatment time. |
97112 + 97110 | Check the current NCCI edit and document each service clearly. |
97162 + 97140 | Document why the treatment was separately reportable from the evaluation. |
97010 + therapy code | Medicare bundles 97010 and does not separately reimburse it. |
Modifier 59 identifies a service that was distinct from another service reported on the same claim. Use it only when the documentation supports a valid distinct-service circumstance.
CMS also provides the more specific X{EPSU} modifiers:
For timed therapy services, the documentation should also support separate treatment time when required. Do not use modifier 59 simply because the services had different diagnoses, treatment goals, or body regions.
Check the current NCCI edit file before billing a code pair together. CMS updates NCCI edits quarterly. XU: Unusual, non-overlapping service
Modifiers add details to a CPT code that the code itself does not show. For physical therapy claims, the correct modifier can identify the plan of care, therapy threshold status, assistant involvement, laterality, or Medicare coverage status.
Modifier | What It Indicates |
GP | Identifies services furnished under an outpatient physical therapy plan of care when required by Medicare claim rules. |
KX | Indicates that continued therapy above the annual Medicare threshold meets the medical necessity requirements for continued payment. |
CQ | Identifies applicable physical therapy services furnished by a physical therapist assistant under Medicare’s PTA billing rules. |
CO | Identifies applicable occupational therapy services furnished by an occupational therapy assistant under Medicare’s OTA billing rules. |
RT / LT | Identifies the right or left side when laterality is required by the code or payer. |
GA | Indicates that a valid Advance Beneficiary Notice (ABN) is on file for an item or service expected to be denied by Medicare. |
GY | Indicates a service that Medicare excludes by statute. |
The GP modifier identifies services furnished under an outpatient physical therapy plan of care. Medicare claim requirements determine when it should be reported. Payer rules should be checked before applying GP to non-Medicare claims.
The KX modifier is used when Medicare-covered therapy continues beyond the applicable annual threshold and the documentation supports continued medical necessity. The 2026 threshold and related documentation requirements are covered in the next section.
CQ applies to applicable physical therapy services involving a physical therapist assistant, while CO applies to applicable occupational therapy services involving an occupational therapy assistant. These modifiers relate to Medicare payment rules and should be applied based on the service and assistant involvement documented in the record.
RT identifies the right side and LT identifies the left side when the payer or coding rules require laterality. Do not assume RT/LT is required for every bilateral therapy service. Check the CPT and payer instructions for the specific claim.
GA indicates that a valid ABN is on file when Medicare is expected to deny the service. GY indicates that the service is statutorily excluded from Medicare coverage. These modifiers serve different coverage purposes and should not be used interchangeably.
Most physical therapy denials come down to a few recurring issues: modifiers, bundling, units, or documentation.
Two denial codes can appear when coding or modifier issues affect payment:
Do not assume the denial code tells you the exact fix. Review the claim, CPT code, modifier, NCCI edits, and supporting documentation first.
If you find a genuine coding or modifier error, submit a corrected claim when the payer’s process allows it.
If the claim was correctly coded and documented, but the payer still denied it, use the payer’s reconsideration or appeal process.
Always follow the payer’s specific filing deadline and correction instructions.
Accurate physical therapy billing codes require the right units, modifiers, documentation, and payer-specific billing rules.
For 2026, keep these points in mind:
A careful pre-submission review can catch many billing issues before they delay payment. When a denial occurs, identify the actual cause first, then follow the payer’s process for a corrected claim or appeal.
Yes. Payers may apply different coverage, authorization, modifier, unit, and reimbursement rules to the same physical therapy CPT code.
Some insurance plans require prior authorization for specific therapy services or visits. Check the patient’s benefits and payer requirements before treatment.
Yes, when both services are separately performed, supported by documentation, and permitted under applicable NCCI and payer billing rules.
Yes, when treatment follows an established plan of care and applicable payer rules do not require reporting an evaluation.
Review CPT, NCCI, Medicare, and payer-specific rules regularly because coding edits and billing requirements can change during the year.
Yes, when the payer permits corrected claims. Follow its specific correction process, filing deadline, and requirements for the identified billing error.
Our certified coders review every CPT code, modifier, and unit calculation before your claim goes out, so payers have no reason to deny it.
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