Fluidized Therapy (Fluidotherapy) — CPB 0450 | AETNA Coverage Update

TL;DR: Aetna, a CVS Health company, modified CPB 0450 covering fluidized therapy (fluidotherapy) effective September 26, 2025. Here's what billing teams need to do.

Aetna updated its fluidized therapy coverage policy under CPB 0450 in the Aetna system, formalizing medical necessity criteria for fluidotherapy applied to extremity conditions. The two primary codes affected are CPT 97036 (Hubbard tank application) and CPT 97113 (aquatic therapy with therapeutic exercise). If your physical therapy or rehabilitation practice bills these codes for Aetna members, this policy defines exactly when you'll get paid—and when you won't.

Quick-Reference Table

Aetna Fluidized Therapy Coverage Criteria and Medical Necessity Requirements 2025

The Aetna fluidized therapy coverage policy under CPB 0450 sets a clear medical necessity bar. Aetna covers fluidotherapy for acute or subacute traumatic or non-traumatic musculoskeletal disorders of the extremities.

That's a specific scope. The treatment must target the extremities—hands, wrists, feet, ankles, forearms, lower legs. Fluidotherapy applied to the spine or trunk doesn't fit this policy. If your documentation describes treatment outside the extremities, expect a claim denial.

The "acute or subacute" qualifier matters too. Chronic, longstanding conditions without active symptom flare may not meet the medical necessity threshold under this policy. Your treatment notes need to reflect the acute or subacute phase clearly—onset, current functional limitations, and clinical rationale for fluidotherapy specifically.

Aetna's policy covers both traumatic and non-traumatic origins. That means post-fracture rehab on a wrist qualifies just as much as rheumatoid arthritis flare in the hands. The 42 covered ICD-10 codes below reflect this breadth—from carpal tunnel syndrome (G56.0–G56.3) to rheumatoid arthritis (M05.x, M06.x) to limb edema following stroke (R22.30–R22.43, R60.0) to hypothermia (T68.xxxA–T68.xxxS).

Prior authorization requirements for fluidotherapy under CPB 0450 are not explicitly detailed in the modified policy summary. Check individual plan documents for your patient population before assuming authorization isn't required. Some Aetna commercial plans impose prior auth even when a procedure meets medical necessity under a clinical policy bulletin.

Reimbursement depends on correct code pairing. CPT 97036 and CPT 97113 are the billing vehicles here. Both bill in 15-minute increments. Document time carefully—underdocumented time units are one of the most common reasons these claims get downgraded or denied.

Coverage Indications at a Glance

Aetna Fluidized Therapy Billing Guidelines and Action Items 2025

This policy is effective September 26, 2025. If your team hasn't aligned charge capture and documentation workflows to this version of CPB 0450 in the Aetna system, do it now.

CPT, HCPCS, and ICD-10 Codes for Fluidized Therapy Under CPB 0450

Covered CPT Codes (When Selection Criteria Are Met)

Both codes bill per 15-minute increment. Use CPT 97036 when fluidotherapy is the modality applied. CPT 97113 covers aquatic therapy with active exercise component—confirm which code fits your specific clinical service before billing.

Key ICD-10-CM Diagnosis Codes

The Real Risk in This Policy

Here's the honest take on CPB 0450: the coverage criteria are reasonable and the ICD-10 code list is generous. Rheumatoid arthritis, carpal tunnel, post-stroke edema, postmastectomy lymphedema—these are common diagnoses in rehab and outpatient PT settings. Billing teams at practices treating these populations should see solid claim approval rates if documentation is tight.

The risk isn't the coverage list. The risk is the extremity requirement and the acute/subacute qualifier. These are the two places where claims will fall through if your documentation is generic. A therapist note that says "fluidotherapy for hand stiffness in RA patient" is far stronger than "PT modalities for arthritis." The first maps directly to this coverage policy. The second invites a medical necessity review.

Fluidotherapy billing under CPB 0450 is straightforward when documentation reflects the clinical picture accurately. The policy isn't punitive—it's defining a scope. Stay within that scope and your denial rate should stay low.