Occupational Therapy Billing Guide: OT Timed Codes, ADL Training, Hand Therapy, Medicare GO Modifier, and OT RCM

OT Timed and Untimed CPT Codes

OT uses many of the same CPT codes as physical therapy, with the treatment focus determining which codes are appropriate: Timed OT codes (8-minute rule, billed per 15 minutes): 97110 — therapeutic exercises (strengthening, ROM, endurance — timed); 97112 — neuromuscular reeducation of movement, balance, coordination, kinesthetic sense, posture, and/or proprioception for sitting and/or standing activities; 97116 — gait training (includes stair climbing); 97530 — therapeutic activities, direct (one-on-one) patient contact; dynamic activities to improve functional performance; this is the primary "functional activity" code and the most commonly used OT timed code; 97533 — sensory integrative techniques to enhance sensory processing; 97535 — self-care/home management training (ADL and IADL); each 15 minutes; this is the OT-specific functional ADL training code — a major differentiator from PT; 97537 — community/work reintegration training including shopping, transportation, money management, avocational activities and/or work environment/process evaluation, direct one-on-one contact; 97542 — wheelchair management/propulsion training; 97750 — physical performance test or measurement with written report; 97755 — assistive technology assessment (e.g., to restore, augment or compensate for existing function, optimize functional tasks and/or maximize environmental accessibility); Untimed OT codes (once per session): 97003 — occupational therapy evaluation, low complexity; 97004 — occupational therapy re-evaluation; 97001 and 97002 are the older evaluation codes — replaced by 97165-97168 in 2017; Current OT evaluation codes (replaced 97001-97004): 97165 — occupational therapy evaluation, low complexity; 97166 — moderate complexity; 97167 — high complexity; 97168 — occupational therapy re-evaluation; Modalities used in OT (many shared with PT): 97010 — hot/cold packs (untimed); 97014 — electrical stimulation (unattended, untimed); 97022 — whirlpool (untimed); 97026 — infrared (untimed); 97032 — electrical stimulation (attended, timed); 97035 — ultrasound (timed); 97036 — Hubbard tank (timed); Documentation for timed OT codes: start and stop times for each timed service; specific techniques used; patient response; skilled justification for each modality; functional goal connection for therapeutic activity codes.

ADL and IADL Training

Activities of daily living (ADL) training is the core of OT's functional domain and what distinguishes OT from PT in documentation: Basic ADL (self-care) — 97535: bathing and grooming training; dressing upper and lower body; functional mobility (bed mobility, transfers); toileting and continence management; feeding and self-feeding (excluding dysphagia treatment, which is SLP domain); personal hygiene and oral care; Instrumental ADL (home management) — 97535 or 97537: meal preparation and kitchen safety; home management (cleaning, laundry, simple home maintenance); financial management and bill paying; medication management; phone use and communication devices; Community/work reintegration — 97537: driving rehabilitation assessment (separate from driving instructor evaluation); community mobility (bus, shopping); return-to-work activity analysis and task modification; Documentation for ADL training: OT documentation must demonstrate skilled intervention: not just "patient practiced dressing" but: "Patient required verbal and tactile cueing at elbow to initiate elbow flexion for donning shirt over hemiparetic left upper extremity. OT modified task sequence to compensate for reduced left shoulder AROM. Patient achieved 3/4 steps independently with setup assistance for remainder; progressed from max assist to mod assist for upper body dressing this session"; functional outcome measures: FIM (Functional Independence Measure) scores by ADL domain; COPM (Canadian Occupational Performance Measure) for patient-identified occupational goals; BI (Barthel Index); Skilled ADL training vs. caregiver training: skilled OT is required when: the patient has a neurological, cognitive, or complex physical condition that requires clinical problem-solving for the ADL approach; compensatory strategies need ongoing adjustment; safety risk requires skilled monitoring; caregiver training alone (without skilled OT intervention) is a less-intensive service and should be documented distinctly.

Hand Therapy and Upper Extremity Rehab

Hand therapy is a specialized area of OT (and some PT) practice focused on upper extremity rehabilitation: CHT certification: Certified Hand Therapist (CHT) is a specialty certification available to OTs and PTs with 4,000 hours of hand therapy experience and passing the HTCC examination; CHT certification is valued by patients and payers but does not change CPT code billing — all hand therapy is billed using standard therapy codes; Common hand therapy conditions: fractures of the distal radius, carpi, metacarpals, and phalanges; flexor and extensor tendon repairs (Zones I-VII); nerve injuries (median, ulnar, radial); crush injuries; arthritis (OA and RA of hand and wrist); trigger finger; Dupuytren's contracture; complex regional pain syndrome (CRPS); carpal tunnel syndrome and cubital tunnel syndrome (post-operative); Hand therapy CPT codes used: 97110 — therapeutic exercise for grip strength, ROM, intrinsic muscle strengthening; 97112 — neuromuscular reeducation for coordination, proprioception after nerve injury; 97530 — therapeutic activities for functional hand use; 97535 — self-care training for adaptive grip techniques; 97760 — orthotic management and training (new orthosis), first 30 minutes; 97761 — prosthetic management and training, each 15 minutes; 97762 — checkout for orthotic/prosthetic use, established patient; 97032 — electrical stimulation attended (for pain, edema, neuromuscular re-ed); 97035 — ultrasound (therapeutic ultrasound for tendon mobilization, scar tissue); Splinting/orthosis fabrication: CPT 97760 covers orthotics management including fabrication of custom splints; when the OT fabricates a custom thermoplastic splint: 97760 covers the fabrication, fitting, and training; the thermoplastic material is included in the practice expense of 97760 (do not separately bill for the material); prefabricated splints that are dispensed to the patient may use L-codes (HCPCS DME codes) in some settings.

Medicare OT Billing Rules

Medicare OT billing requires specific modifier use and compliance with the separate OT therapy cap: Modifier GO requirement: Modifier GO (services delivered under an outpatient occupational therapy plan of care) is required on all Medicare OT claims; analogous to Modifier GP (PT) and Modifier SZ (SLP); claims without Modifier GO are rejected; OT therapy cap: Medicare imposes a separate annual therapy cap for OT services (approximately $3,000 in 2026, adjusted annually); the OT cap is separate from the combined PT/SLP cap; once the OT threshold is met, Modifier KX must be appended to certify medical necessity; without KX, claims above the threshold are denied; KX modifier documentation: the treating OT must document in the patient's record that continued services are medically necessary and the plan of care supports the ongoing need; this documentation is the basis for the KX certification; Functional limitation G-codes (historical context): from 2013-2019, Medicare required functional limitation G-codes and severity modifiers on therapy claims to report patient functional status at evaluation, every 10 treatment sessions, and at discharge; CMS eliminated the G-code requirement effective January 1, 2020; only current code billing and KX modifier requirements remain active; Physician plan of care certification: a physician or NPP must certify the OT plan of care; initial certification within 30 days; recertification every 90 days; the plan of care must include: diagnosis; long-term treatment goals; type, amount, duration, and frequency of therapy; Supervision of OTAs: Medicare requires "general supervision" of OTAs by the supervising OT (the OT must be available but does not need to be present); contrast with PT/PTA where CMS has changed supervision requirements over time; verify current CMS OTA supervision requirements at the time of service; Setting-specific billing rules: hospital outpatient: bill under facility NPI with revenue code 434 (OT services); physician office: bill under physician practice NPI; private OT practice: bill under OT practice NPI; SNF: Part A covers OT under the consolidated billing requirement; Part B OT is available for skilled nursing facility residents not in a Part A covered stay.

OTA Billing and Modifier CO

Occupational therapy assistants (OTAs) face the same Medicare payment differential as PTAs starting January 1, 2022: Modifier CO requirement: Modifier CO (services delivered by an occupational therapy assistant) is required when an OTA provides Medicare Part B OT services; without Modifier CO, Medicare pays the full OT rate; with Modifier CO, Medicare pays 85% of the fee schedule amount; this is the same structure as PTA billing under Modifier CQ; When to use Modifier CO: Modifier CO applies when: a certified OTA performs the service; under Medicare Part B in outpatient settings; it does NOT apply when: the supervising OT performs the service directly; in settings where OTAs are not recognized (some payers); when OTA services are covered under different rules (Medicaid, some commercial plans); Documentation for OTA-delivered services: the OTA must document the services provided; the supervising OT must review and co-sign at intervals required by the state practice act and Medicare conditions of participation; the plan of care remains the OT's responsibility; OTA billing in non-Medicare settings: commercial payers may not recognize Modifier CO or the 85% reduction; most commercial payers pay OTA services at the full OT rate; Medicaid OTA coverage varies by state; verify per-payer rules for OTA billing; Clinical implications: the 85% payment differential creates an economic consideration for practices employing OTAs under Medicare; for patients nearing or exceeding the annual therapy cap, the 15% savings per OTA-delivered unit can extend the available cap further; practices must track whether services were OT- or OTA-delivered and append the appropriate modifier consistently.