Physical therapy medical billing services
Every treatment minute has to be counted, attributed and defended — and a plan of care that lapses invalidates everything billed after it.
Also called: Physiotherapy · Rehabilitation Therapy. We keep one page per specialty rather than a page per name.
Why physical therapy billing is different
Physical therapy is billed in units of time, and the unit maths is unforgiving. Timed codes convert treatment minutes into billable units under the 8-minute rule; untimed codes are one unit regardless of duration. Mixing them in one session, with remainder minutes carried across timed codes, produces a calculation most practice-management systems do not do correctly on their own. Under-count and the clinic gives away treatment it delivered. Over-count and it is a unit denial at best, an audit finding at worst.
The plan of care is the second failure point, and it is the expensive one. Therapy has to be delivered under a plan certified by the referring provider, with re-certification at defined intervals. When certification lapses, everything billed after the lapse is denied — retroactively, in bulk, often months later.
Third, this is a specialty of limits. Visit caps, annual thresholds requiring the KX modifier, and authorisation renewals mid-course all mean that a clinic can deliver a clinically correct course of care and be paid for only part of it.
Codes we work with
The families this specialty actually bills, and where each one carries a rule worth knowing.
| Family | Range | Notes |
|---|---|---|
| Evaluations | 97161–97163 | Low, moderate and high complexity |
| Re-evaluation | 97164 | Requires a documented change in status or plan |
| Therapeutic procedures, timed | 97110, 97112, 97116, 97530, 97535 | Billed in 15-minute units under the 8-minute rule |
| Manual therapy, timed | 97140 | Frequently paired with 97530 and requires a distinct-service modifier |
| Modalities, supervised and untimed | 97010, 97012, 97014, 97018 | One unit per session regardless of time |
| Modalities, constant attendance and timed | 97032–97036 | Requires direct one-to-one contact |
| Group therapy | 97150 | Untimed, two or more patients |
| Dry needling | 20560, 20561 | Coverage varies significantly by payer |
| Orthotics and prosthetics management | 97760–97763 | Timed, with fitting and training documented |
Modifiers that matter
And the specific way each one is most often misused in this specialty.
| Modifier | Use | Common error |
|---|---|---|
| GP | Services delivered under an outpatient physical therapy plan of care | Omitted, which denies the claim outright with most payers |
| KX | Services above the annual threshold remain medically necessary | Not applied once the threshold is crossed, so the rest of the course denies |
| 59 / XU | Distinct procedural service | Missing on 97140 billed with 97530 in the same session |
| CQ / CO | Service furnished in whole or part by a PTA or OTA | Not applied where required, or applied to the wrong portion of the units |
| 96 / 97 | Habilitative or rehabilitative service | Required by many plans and routinely omitted |
Top denial reasons
With the CARC code you will see on the remittance, and what we do to stop each one recurring.
| Denial | CARC | How we prevent it |
|---|---|---|
| Units exceed what the treatment minutes support | CO-151 | Unit calculation validated against documented total timed minutes |
| Plan of care not certified or expired | CO-B15, CO-50 | Certification and re-certification dates tracked per patient, with advance alerts |
| Visit limit or authorisation exhausted | CO-197, CO-119 | Remaining authorised visits reported weekly and re-authorised before the last one |
| Missing therapy or threshold modifier | CO-4 | GP and KX applied by rule, not by memory |
| Manual therapy bundled into another timed procedure | CO-97 | Distinct-service modifier applied where the documentation supports separate work |
Prior authorisation in this specialty
Most commercial plans authorise physical therapy in blocks of visits, and the block runs out mid-course. The failure mode is entirely predictable: the clinic treats through the last authorised visit, requests more, and the gap between request and approval is delivered unpaid. We track remaining authorised visits per patient, file the extension request before the final covered visit with the objective progress measures payers ask for, and flag the plan-of-care re-certification date at the same time so both renew together.
Where revenue leaks
- Timed units under-counted because remainder minutes were not carried correctly
- Whole courses of care denied retroactively after a plan-of-care certification lapsed
- Treatment delivered past an exhausted visit authorisation
- The KX threshold crossed without the modifier, denying the remainder of the year
What we do for physical therapy practices
The parts of the cycle where this specialty gains the most, framed for how it actually bills.
Prior Authorization Services
Auth requests submitted, tracked, and escalated so procedures aren't delayed.
See prior authorizationDenial Management & Appeals
Root-cause analysis, corrected claims, and clinical appeals filed inside payer deadlines.
See denial managementMedical Coding
Certified CPC and CCS coders assign and validate ICD-10, CPT, and HCPCS codes from your documentation.
See medical codingEligibility & Benefits Verification
Coverage and benefits confirmed before the visit, not after the denial.
See eligibility verificationSee what this specialty is losing in your practice
We run the analysis against physical therapy benchmarks, not a generic template. Send 90 days of claims data and keep the report either way.
Questions about physical therapy billing
Do you calculate units under the 8-minute rule?
Yes, from documented total timed minutes, with remainder minutes carried correctly across timed codes.
Will you track plan of care certification?
Yes. Certification and re-certification dates are tracked per patient with advance alerts, because a lapse invalidates everything billed after it.
Can you manage visit authorisations?
Yes. Remaining authorised visits are reported weekly and extensions are filed before the last covered visit.
Do you handle the KX threshold?
Yes. The modifier is applied by rule once the annual threshold is crossed, so the remainder of the year is not denied.
Adjacent specialties
Specialties whose billing shares rules, payers or authorisation patterns with this one.