Physical Therapy Billing Services

Physical therapy billing runs on time. Most treatment codes are counted in 15-minute units, so one missed minute in a note can change what a payer will allow. Add plan of care dates, visit caps, and therapy-specific modifiers, and small errors pile up fast.

Good physical therapy medical billing starts at the front desk with benefit checks and authorization tracking. It continues through accurate unit counts, clean claims, and steady follow-up on denials. Westmont connects PT practices with vetted billing experts who work in outpatient therapy every day. They know how Medicare, commercial plans, workers' compensation, and auto carriers each handle therapy claims, and they can fit your clinic's size and software.

Who this is for

• Independent outpatient physical therapy clinics
• Multi-location PT groups and rehab networks
• Physical therapists in private practice, from solo to large teams
• Hospital-based outpatient therapy departments
• Mobile and home-based PT providers
• Practices that also treat workers' compensation or auto injury patients

What gets billed

• Initial evaluations at low, moderate, and high complexity
• Re-evaluations when a patient's status changes
• Therapeutic exercise
• Neuromuscular re-education
• Manual therapy techniques
• Therapeutic activities
• Gait training
• Electrical stimulation, attended and unattended
• Ultrasound and other physical agents
• Self-care and home management training
• Group therapy sessions
• Dry needling, where payers allow it

Commonly billed codes

Code	Type	What it covers
97161	CPT	PT evaluation, low complexity
97162	CPT	PT evaluation, moderate complexity
97163	CPT	PT evaluation, high complexity
97164	CPT	PT re-evaluation of an established plan of care
97110	CPT	Therapeutic exercise, each 15 minutes
97112	CPT	Neuromuscular re-education, each 15 minutes
97140	CPT	Manual therapy, each 15 minutes
97530	CPT	Therapeutic activities, each 15 minutes
97035	CPT	Ultrasound, each 15 minutes
GP	Modifier	Marks services delivered under a physical therapy plan of care
KX	Modifier	Used on Medicare claims above the annual therapy threshold when care is still medically necessary
M54.50	ICD-10-CM	Low back pain, unspecified
M25.511	ICD-10-CM	Pain in the right shoulder

Note

Codes are examples for orientation, not a complete list, and do not guarantee coverage or payment. Always check current code sets and payer policy.

Billing challenges in physical therapy

Timed-code unit counting. Medicare and many payers count total timed minutes to decide how many units to bill. A biller experienced in therapy applies the correct rule for each payer and checks notes against units before a claim goes out.

Plan of care and certification. Medicare generally expects a signed plan of care and timely recertification. Billers track those dates so visits are not billed outside a valid certification period.

Therapy thresholds and the KX modifier. Medicare sets annual threshold amounts that change each year. When a patient passes the threshold, the claim needs the right modifier and notes that show medical necessity. Check current-year updates.

Assistant billing. Services furnished by physical therapist assistants often need a specific modifier and may be paid at a reduced rate. A skilled biller applies this consistently by payer.

Bundling and edit conflicts. Some pairs of codes, such as manual therapy and other services on the same day, trigger edits. Billers learn each payer's edits and use modifiers only when the record supports them.

Visit limits and authorizations. Many commercial plans cap therapy visits or require reauthorization. Tracking these limits prevents denials after the care has already been given.

Direct access and referral rules. State rules on direct access vary, and some payers still ask for a referral. Billers confirm requirements before the first visit.

Mixed payer types. Auto and workers' compensation claims follow different forms, timelines, and fee schedules than health plan claims. Specialty billers keep these workflows separate.

How Westmont can help

• Matching your clinic with vetted billing experts experienced in physical therapy billing
• End-to-end revenue cycle support, from eligibility checks to payment posting
• Denial management and appeals for therapy-specific rejections
• Help with payer credentialing and enrollment for new therapists
• Reporting that fits how your clinic tracks visits, units, and A/R

Frequently asked questions

What is the 8-minute rule in physical therapy billing?

It is a Medicare method for turning total timed minutes into billable units. Roughly, at least eight minutes of a timed service earns one unit, and total minutes across all timed codes decide the final count. Some commercial payers use a different method, so confirm each payer's rule and review current-year Medicare guidance.

Do I need a physician referral to bill for physical therapy?

It depends on your state and the payer. Many states allow some form of direct access, but Medicare generally expects care under a certified plan of care, and some commercial plans still require a referral or authorization. Check state law and each payer's policy before the first visit.

What does the GP modifier mean?

GP shows that a service was delivered under a physical therapy plan of care. Medicare requires it on therapy claims, and some other payers do as well. Occupational and speech therapy use different modifiers. Using the wrong one is a common cause of rejected claims.

Why do physical therapy claims get denied?

Common reasons include missing authorizations, visits beyond a plan's limit, unit counts that do not match notes, expired certifications, and incorrect modifiers. A physical therapy billing company can review denials for patterns and fix the process that causes them, not just resubmit the claim.

Can a billing partner work with my existing practice software?

Often, yes. Many billing experts work inside the electronic health record or billing system a clinic already uses. When you contact Westmont, tell us which software you run, and we will look for experts who are comfortable with it.

Related billing services

• Occupational Therapy
• Speech-Language Pathology
• Chiropractic
• Physical Medicine & Rehabilitation
• Orthopedic Surgery
• Sports Medicine