CPT 97018Physical Therapy

Paraffin bath therapy

CPT code 97018 covers paraffin bath therapy, a heat treatment where a patient's hand or foot is dipped into warm, melted paraffin wax to relieve pain and stiffness in joints and muscles.

Showing rates for

National Average

Base Medicare rate

$6.15

This calculator gives a typical-case estimate using standard Medicare modifier rules. Actual payment depends on payer policies, documentation, code-specific CMS status indicators, and locality. Verify before billing.

RVU breakdown

Work RVU

0.06

PE RVU (NF)

0.12

MP RVU

0.01

Total RVU

0.19

Conversion factor: 32.3465 · Source: CMS MPFS RVU25A · Confidence: High

NCCI bundling edits

Loading bundling edits…

Billing tips

Bill one unit per session regardless of duration; 97018 is not time-based and cannot be billed in multiple units for extended treatment time
Impact: Prevents upcoding audits and denials; billing 2 units when only 1 is appropriate risks $6.15 overpayment recoupment
Document the specific body part treated (hand, foot, elbow, etc.) and medical necessity linking to diagnosis codes such as M06.9 (rheumatoid arthritis) or M25.50 (joint pain)
Impact: Reduces denial rate by 40-60% based on LCD compliance
Always bill with appropriate therapy modifier (GP for PT, GO for OT) as Medicare requires designation of therapy discipline
Impact: Claims without therapy modifiers may reject entirely, delaying payment by 15-30 days
Consider bundling paraffin bath with manual therapy or therapeutic exercise in the same session for better revenue; separately bill therapeutic codes that are time-based
Impact: A 30-minute manual therapy session (97140) reimburses $31.44, combined with 97018 yields $37.59 total per patient visit
Track when Medicare therapy threshold is approaching ($2,150 annually); prepare KX modifier documentation before submitting claims that exceed cap
Impact: Prevents automatic denials and payment delays on claims submitted after threshold is reached
Do not bill 97018 on the same day as other heat/cold modalities (97010, 97014) unless clearly distinct and separately documented treatments
Impact: Bundling edits may reduce payment to $0 for the secondary modality; LCD policies often limit one passive modality per session

Live Field Datano reports yet

Real billers contribute denial patterns and appeal strategies for this code. Once 5+ reports come in, you’ll see live aggregated data here — the only place this exists, free.

Working with CPT 97018?

Get the free Revenue Protection Toolkit — the denial triggers, modifier pitfalls, and bundling conflicts that quietly cost you reimbursement. Instant download.

Help build the field knowledge

MedPayIQ gets smarter as billers contribute. If you've had this code denied, share what happened so others learn from it. Anonymous, no patient info.

Related actions

Frequently asked questions

How much does Medicare pay for CPT code 97018 in 2025?

Medicare pays $6.15 for CPT code 97018 in 2025 under both facility and non-facility settings. This rate is based on 0.19 total RVUs multiplied by the 2025 conversion factor of 32.3465.

Is paraffin bath therapy covered by Medicare?

Yes, Medicare covers paraffin bath therapy (97018) when medically necessary as part of a skilled physical or occupational therapy plan of care. Coverage requires documentation showing the treatment addresses functional limitations and is not merely maintenance therapy.

Can you bill CPT 97018 multiple times per day?

Generally no. CPT 97018 is billed as one unit per treatment session regardless of duration. Billing multiple units in the same session is not appropriate unless treating distinctly separate anatomical areas with clear documentation and proper modifiers.

What modifiers are required for billing CPT code 97018?

CPT 97018 requires a therapy discipline modifier: GP for physical therapy or GO for occupational therapy. Additional modifiers like RT/LT (right/left) may be used for laterality, and KX when exceeding Medicare therapy thresholds with documented medical necessity.

Is CPT 97018 a timed code or untimed code?

CPT 97018 is an untimed code. Unlike many therapy procedures that are billed in 15-minute units, paraffin bath is billed as one unit per treatment session regardless of how long the patient's extremity remains in the wax or wrapped.

What diagnosis codes support medical necessity for CPT 97018?

Common supporting diagnoses include M06.9 (rheumatoid arthritis), M15.9 (osteoarthritis), M25.50 (joint pain), M79.3 (panniculitis), M34.9 (scleroderma), and post-surgical rehabilitation codes. Documentation must link the paraffin bath to functional improvement related to the diagnosis.

Can physical therapy assistants perform paraffin bath therapy?

Yes, physical therapy assistants (PTAs) and occupational therapy assistants (COTAs) can perform paraffin bath therapy under appropriate supervision as defined by state practice acts. The supervising therapist or physician must establish the plan of care and provide required oversight.