Physical therapy billing turns a 45-minute visit into units, and whether that visit pays as two units or three can depend on nothing more than which payer’s counting rule the billing system applied. Most PT treatment codes are timed in 15-minute increments, so total minutes, minutes per code, and the payer’s conversion method decide what the practice collects long before anyone looks at the fee schedule.
Key Takeaways
- PT evaluations bill once by complexity (97161, 97162, 97163), while most treatment codes are timed in 15-minute units.
- Medicare converts total timed minutes to units under the 8-minute rule, and many commercial payers count minutes per code instead.
- Medicare requires the GP modifier on PT services and pays lines with the CQ modifier, for services a PTA helped furnish, at 85%.
- Claims above Medicare’s annual therapy threshold need the KX modifier and documented medical necessity.
- Each PT needs their own Medicare and commercial enrollment, while PTAs bill under the supervising PT.
Physical Therapy CPT Codes
PT evaluations are untimed and billed once at the complexity the documentation supports, based on the patient’s history, the body systems examined, clinical presentation, and decision-making. A re-evaluation (97164) is billed only when there’s a new clinical finding, a significant change in condition, or a failure to respond to treatment. A scheduled progress check doesn’t qualify.
These codes make up most PT claims.
- 97161, 97162, and 97163 (PT evaluation, low, moderate, and high complexity)
- 97164 (PT re-evaluation)
- 97110 (therapeutic exercise, each 15 minutes)
- 97112 (neuromuscular re-education, each 15 minutes)
- 97116 (gait training, each 15 minutes)
- 97140 (manual therapy techniques, each 15 minutes)
- 97530 (therapeutic activities, each 15 minutes)
- 97535 (self-care and home management training, each 15 minutes)
- 97032 (attended electrical stimulation, each 15 minutes)
- 97014 and G0283 (unattended electrical stimulation, with G0283 used for Medicare)
Hot and cold packs (97010) are bundled under Medicare and aren’t separately payable. Dry needling bills as 20560 or 20561. Medicare covers it only for chronic low back pain under its acupuncture rules, and physical therapists can’t bill Medicare for it. Many commercial plans exclude it as well, so patients should know they may owe the full charge before treatment.
The 8-Minute Rule and Timed Units
Medicare adds up all timed minutes for the visit and converts the total to units. Eight to 22 minutes is one unit, 23 to 37 is two, 38 to 52 is three, and so on in 15-minute steps. The units are then assigned to codes based on how the time was split, so a code with fewer than 8 minutes on its own can still receive a unit when the remaining minutes justify it.
Many commercial payers follow the AMA’s per-code approach instead. Each timed code needs at least 8 minutes of its own to bill a unit, and leftover minutes aren’t combined across codes. A visit with 20 minutes of therapeutic exercise and 7 minutes of manual therapy bills two units under Medicare’s method but only one under the per-code method, so the billing system has to apply the right rule for each payer.
Untimed codes, including evaluations and unattended electrical stimulation, don’t count toward the timed total. Every note needs total timed minutes, minutes for each timed code, and total treatment time.
Payment reductions and code pairs
Medicare applies a multiple procedure payment reduction when a patient receives more than one unit of therapy on the same day. The first unit pays in full, and the practice expense portion of each additional unit is cut by 50 percent, so a four-unit visit doesn’t pay four times the single-unit rate.
Some timed codes also trip NCCI edits when billed together. Manual therapy (97140) and therapeutic activities (97530) on the same date are a common pair, and they need modifier 59 or an X modifier only when the services were separate and distinct, with each one’s minutes documented.
Medicare Modifiers and the Plan of Care
Every PT service billed to Medicare carries the GP modifier. When a physical therapist assistant furnishes more than 10% of a service, the line also needs the CQ modifier, and Medicare pays it at 85% of the fee schedule. A missing CQ where one is required is an overpayment, and adding one where it isn’t needed costs the practice 15% on that line.
The therapy cap was repealed in 2018, but Medicare still sets an annual threshold that physical therapy shares with speech-language pathology. Claims above it need the KX modifier, which attests that the services are medically necessary and documented, and spending above $3,000 in a year can trigger targeted medical review.
Patients can see a PT without a physician referral in every state, but Medicare still requires a plan of care certified by a physician or NPP, generally within 30 days of the evaluation and recertified at least every 90 days. A progress report is due at least once every 10 treatment visits. Visits outside a certified plan of care can be denied even when the treatment itself was appropriate. The same plan of care rules apply to occupational therapy and speech therapy.
Remote Therapeutic Monitoring
Physical therapists can bill remote therapeutic monitoring to track home exercise adherence and pain or function between visits. RTM bills under its own device supply and treatment management codes, carries the GP modifier like other PT services, and can’t be billed for a patient who is receiving remote physiologic monitoring in the same period.
Commercial Plans, Workers’ Comp, and Auto Claims
Many commercial plans limit PT visits per year and require authorization after the evaluation or after a set number of visits, often through a separate utilization management company. Authorizations usually approve a number of visits within a date range, and visits past either limit are denied. An approval also has to match what’s billed, which we cover in why an approved authorization can still end in a denied claim.
Workers’ compensation and auto no-fault claims make up a large share of PT revenue at many practices. They follow state fee schedules and claim forms rather than health plan rules, need the claim number and adjuster information on file, and often require progress reports sent directly to the carrier before more visits are approved.
Payer Contracting for PT Practices
PT fee schedules are often set well below Medicare for the same codes, and a small difference on 97110 or 97140 adds up fast at the volume a busy clinic bills. Payer contracting reviews should compare the practice’s most-billed timed codes against Medicare and local benchmarks, and check which unit rule each contract uses, since a per-code counting method lowers revenue on the same visit.
Physical Therapist Credentialing
Licensure and enrollment
Payers verify each PT’s state license and, where applicable, board certification from the American Board of Physical Therapy Specialties, such as orthopedic (OCS), neurologic (NCS), or sports (SCS) certification. Physical therapists in private practice enroll with Medicare individually through PECOS and reassign benefits to their group, and the group enrolls as well.
Physical therapist assistants
PTAs don’t enroll with Medicare and can’t bill under their own number. Their services are billed under the supervising PT with the CQ modifier. Since 2025, Medicare allows general supervision of PTAs in private practice, but state practice acts and some commercial plans still require closer supervision, and the stricter rule applies.
Commercial networks
Each commercial and Medicaid managed care plan credentials PTs separately, usually through CAQH ProView, and some plans route PT through a contracted network manager with its own enrollment. Until a plan approves the PT, their visits can’t be billed to it, which is why you can’t bill what you can’t credential.
Physical Therapy Billing FAQs
What is the 8-minute rule in physical therapy billing?
It’s Medicare’s method for converting timed treatment minutes to units. Total timed minutes are added together, and 8 to 22 minutes equals one unit, 23 to 37 equals two, and so on. Many commercial payers count minutes per code instead.
Does Medicare still have a therapy cap?
No. The cap was repealed in 2018. Medicare now uses an annual threshold, shared with speech therapy, above which claims need the KX modifier and documentation of medical necessity.
When is the CQ modifier required?
When a physical therapist assistant furnishes more than 10% of a service billed to Medicare. Medicare pays CQ lines at 85% of the fee schedule amount.
Why doesn’t a four-unit PT visit pay four times the single-unit rate?
Medicare’s multiple procedure payment reduction pays the first unit in full and cuts the practice expense portion of each additional unit by 50 percent on the same day.
When can a PT re-evaluation be billed?
Only when there’s a new clinical finding, a significant change in the patient’s condition, or a failure to respond to the plan of care. Routine progress reports aren’t billed as re-evaluations.
Does Medicare cover dry needling?
Only for chronic low back pain, under the same rules as acupuncture, and a physical therapist can’t bill Medicare for it. Dry needling bills as 20560 or 20561, and many commercial plans exclude it, so patients should be told about the cost before treatment.
Why PTs Hand Their Billing to Medwave
Medwave applies the right unit rule for each payer, adds GP, CQ, and KX where they belong, and flags expiring certifications and used-up authorized visits before a claim goes out against them. Our PT billing clients see 98% of claims accepted on first submission.
Some plans route therapy credentialing through a network manager instead of the plan itself, and our credentialing team handles both paths. A new PT is usually enrolled in about 85 days.
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