Specialty billing
Physical Therapy Medical Billing Services
Physical therapy billing is governed by the eight-minute rule, which converts documented treatment time into billable units for timed codes. Because PT is high-frequency and unit-based, small systematic errors in time documentation or modifier use compound across every patient on the schedule.
Physical Therapy benchmarks
- Typical denial rate
- 12–18%
- Days in AR
- 35–48
- Achievable clean claim rate
- 97%+
Typical ranges for physical therapy practices. Your actual numbers are measured during the audit.
The complexity
Why physical therapy is uniquely difficult to bill
Timed codes convert documented minutes into units under the eight-minute rule
Untimed codes bill one unit per session regardless of duration
Therapy caps require the KX modifier once thresholds are exceeded
Plan of care requires physician certification and periodic recertification
Authorization visit counts must be tracked and extended before they are exhausted
NCCI edits restrict which therapeutic codes may be billed together on the same day
Coding
Physical Therapy procedure codes we work with daily
A representative sample, not an exhaustive list. Coders are assigned by specialty rather than pooled.
| Code | Description |
|---|---|
| 97110 | Therapeutic exercise, each 15 minutes |
| 97140 | Manual therapy techniques, each 15 minutes |
| 97530 | Therapeutic activities, each 15 minutes |
| 97162 | Physical therapy evaluation, moderate complexity |
| 97012 | Mechanical traction, supervised untimed modality |
| 97535 | Self-care and home management training, each 15 minutes |
Revenue leakage
Where physical therapy practices lose money
These are the denial patterns specific to this specialty — the ones a general-purpose billing service will not be looking for.
Eight-minute rule errors
Units billed exceeding what total documented treatment time supports, the most common cause of PT overpayment recoupment.
Missing KX modifier
Claims denied after the therapy threshold is exceeded because the KX modifier attesting medical necessity was not appended.
Certification lapses
Services denied because the plan of care was not certified or recertified by the referring physician within the required window.
Authorization exhausted
Visits delivered beyond the authorized count because remaining visits were not tracked and extension was not requested in time.
NCCI pair edits
Therapeutic codes billed together that NCCI edits bundle, without documentation supporting modifier 59 or an X modifier.
Payer landscape
What physical therapy practices need to know about payers
Payer policy drives more physical therapy denials than coding does. Knowing the policy before the service is what prevents them.
- Medicare applies annual therapy thresholds above which the KX modifier is required to attest continued medical necessity.
- Commercial payers commonly authorize a fixed visit count per episode; extensions must be requested before exhaustion, not after.
- Plan of care certification requirements and timelines vary between Medicare and commercial payers.
Proof
A physical therapy practice we worked with
Summit Physical Therapy achieves a 99% clean claim rate
Authorization requirements were being missed routinely, producing denials on care already delivered. High patient volume made it impractical for front-desk staff to verify coverage and remaining authorized visits before each appointment.
We implemented automated eligibility verification at check-in, built an authorization tracking system flagging patients approaching their visit limit, and trained front-desk staff on verification protocol.
Results
- Clean claim rate improved to 99%
- Authorization-related denials eliminated
- Patient satisfaction increased with clearer billing communication
- Revenue cycle time reduced from 45 days to 16
Michael Anderson, PT, Clinic Owner · Boulder, CO
Questions
Physical Therapy billing FAQ
Last updated August 20, 2026
Reviewed by a certified coding leadTimed codes bill in 15-minute units, but a unit is supported once at least 8 minutes of that increment is delivered. Total timed minutes across all timed codes determine total billable units: 8–22 minutes supports 1 unit, 23–37 supports 2, 38–52 supports 3, and so on. Untimed codes bill one unit each regardless of time and are excluded from the calculation.
The KX modifier attests that services above the annual Medicare therapy threshold remain medically necessary and that documentation supports it. Once a patient crosses the threshold, claims without KX deny. Tracking cumulative therapy dollars per patient per year is what prevents this — it cannot be caught at the claim level.
Almost always for unit counts unsupported by documented time. Auditors recalculate units from the documented minutes in the note. If treatment time is recorded loosely — or recorded per code rather than in total — the recalculation frequently produces fewer units than were billed, and the difference is recouped across the sampled period.
We maintain remaining authorized visits per patient per episode and flag when a patient approaches exhaustion, so extension is requested before the visit is delivered. Requesting after the fact rarely succeeds, and the delivered visits are usually unrecoverable.
Primary sources
Coverage, rates and local policy for physical therapy, at the source.
- Medicare Benefit Policy Manual (opens in a new tab)
Centers for Medicare & Medicaid Services — What Medicare covers and under what conditions, as distinct from how a claim is processed. The starting point for any coverage or medical necessity question.
- Medically Unlikely Edits (MUE) tables (opens in a new tab)
Centers for Medicare & Medicaid Services — The maximum units of a code payable for one patient on one day. Unit-based denials usually trace to this table rather than to a coding error.
- Medicare Coverage Database (LCD/NCD) (opens in a new tab)
Centers for Medicare & Medicaid Services — Searchable national and local coverage determinations. The direct answer to whether a diagnosis supports medical necessity for a given procedure.
Services physical therapy practices use most
Get a free physical therapy billing audit
We'll review your physical therapy denial patterns, coding accuracy and AR aging against the benchmarks above. Takes about two minutes to request.
No setup fees · You pay when we collect · Pricing from 3% of net collections