ModifiedUnitedHealthcarePolicy CS132OH.C

Noncontact Warming Therapy, Ultrasound Therapy, and Fluorescence Imaging for Wounds (for Ohio Only)

Policy governs coverage and medical necessity of noncontact normothermic wound warming therapy, low-frequency (noncontact and contact) ultrasound therapy, and noncontact real-time fluorescence wound imaging for bacterial presence for members in Ohio.

Policy Summary

PayerUnitedHealthcare

PolicyNoncontact Warming Therapy, Ultrasound Therapy, and Fluorescence Imaging for Wounds (for Ohio Only)

Policy CodePolicy CS132OH.C

Change TypeSupporting information and references updated

Effective DateSep 1, 2025

Next Review DateN/A

Key ActionVerify plan-specific federal, state (Ohio Administrative Code), and contractual prior authorization requirements before submitting requests for these services.

SourceLink

POLICY UPDATE CHANGES

Supporting Information Updated Clinical Evidence and References sections to reflect the most current information; previous policy version CS132OH.B archived.

3interventions evaluated

Ohiostate-specific applicability

insufficientcoverage stance

6codes listed

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multicenter RCT participants

Coverage Determination and Rationale

Not medically necessary — warming therapy, low-frequency ultrasound, fluorescence imaging

Covered when ALL of the following are met:

Warming therapy (NNWT): Warming therapy or noncontact normothermic wound therapy (NNWT) is unproven and not medically necessary for treating wounds due to insufficient evidence of efficacy.

Supported by policy coverage rationale stating NNWT is unproven and not medically necessary.

Low frequency ultrasound therapy is unproven and not medically necessary for treating wounds due to insufficient evidence of efficacy.

Supported by policy coverage rationale stating low frequency ultrasound is unproven and not medically necessary.

Noncontact real-time fluorescence wound imaging for bacterial presence is unproven and not medically necessary due to insufficient evidence of safety and/or efficacy.

Supported by policy coverage rationale stating fluorescence imaging is unproven and not medically necessary.

Adjunctive therapy evidence summary

Summary of clinical findings informing coverage stance:

Low-frequency ultrasound evidence: Randomized pilot data (small DFU trial) suggested noncontact low-frequency ultrasound (NCLF‑US) applied three times weekly reduced wound area in a very small diabetic foot ulcer (DFU) study (greatest PAR ~86%), but a larger multicenter RCT of weekly low‑dose, high‑frequency ultrasound for venous leg ulcers (n=337) showed no increase in healing rates, no improvement in quality of life, and significantly more adverse events; overall evidence is inconsistent and insufficient for routine use.

See Yao et al. (small RCT) and Watson et al. (large RCT).

Fluorescence imaging evidence: Observational studies and trial analyses report that fluorescence imaging (e.g., MolecuLight i:X) increases detection sensitivity for bacterial loads (device sensitivity rises for loads ≈10^4 CFU/g and peaks near 92.6% at >10^8 CFU/g) and may identify peri‑wound high loads missed by clinical signs; however, an independent evidence assessment (ECRI) concluded current evidence is inconclusive regarding improvement in patient‑centered outcomes and additional randomized trials are needed.

See Armstrong et al., Le et al., and ECRI assessment.

The list of CPT/HCPCS and other procedure codes included in this policy (for example, 0598T, 0599T, 97610, A6000, E0231, E0232) is provided for reference only. Inclusion of a code in this document does not imply that the service described by the code is covered, nor does it guarantee reimbursement. Benefit coverage is determined by applicable federal, state, or contractual requirements and other policies that may apply.

Clinical evidence assessments (for example, by ECRI) conclude that current studies of handheld fluorescence imaging devices such as the MolecuLight i:X are inconclusive for demonstrating improved patient-centered outcomes. While these devices may increase detection of wounds that harbor higher bacterial loads, published studies are limited and additional randomized controlled trials are needed to confirm safety and efficacy before routine coverage can be supported.

Professional society guidance does not include these adjunctive technologies as standard treatment options. The American Podiatric Medical Association (in collaboration with the Society for Vascular Surgery and the Society for Vascular Medicine) does not include warming therapy (NNWT) or low-frequency ultrasound in its diabetic foot management recommendations. Similarly, NICE Medtech guidance and technology briefings state the evidence for devices such as MolecuLight i:X and the MIST Therapy System is limited and not sufficient to support routine adoption.

Summary: Noncontact normothermic wound therapy (NNWT), low-frequency ultrasound, and noncontact real-time fluorescence wound imaging are considered unproven and not medically necessary due to insufficient evidence of efficacy and/or safety. Available studies are limited by small sample sizes, heterogeneity, and a lack of confirmatory randomized trials showing improved patient-centered outcomes.

A multicenter randomized controlled trial of weekly, low-dose, high-frequency therapeutic ultrasound added to standard care for hard-to-heal venous leg ulcers (n = 337) found no significant difference in time to healing or recurrence compared with standard care alone, and reported significantly more adverse events in the ultrasound group. The authors concluded that weekly low-dose, high-frequency ultrasound for 12 weeks did not increase ulcer healing rates or improve quality of life.

The NICE Medtech Innovation Briefing and related assessments note limited evidence that the MolecuLight i:X reduces wound closure time or improves antibiotic stewardship. Overall, technology briefings conclude that current evidence is insufficient to demonstrate clinical utility for improving patient-centered outcomes and recommend further higher-quality studies.

Applicable Procedure and Billing Codes (Reference)

Applicable CPT/HCPCS Codes (listed for reference)mixed

0598T	Noncontact real-time fluorescence wound imaging, for bacterial presence, location, and load, per session; first anatomic site
0599T	Noncontact real-time fluorescence wound imaging; for bacterial presence, location, and load, per session; each additional anatomic site
97610	Low frequency, non-contact; non-thermal ultrasound, including topical application(s), when performed, wound assessment; and instruction(s) for ongoing care, per day
A6000	Noncontact wound-warming wound cover for use with the noncontact wound-warming device and warming card
E0231	Noncontact wound-warming device (temperature control unit; AC adapter and power cord) for use with warming card and wound cover
E0232	Warming card for use with the noncontact wound-warming device and noncontact wound warming-wound cover

Bacterial load thresholds — detection and concern thresholds

Device detection thresholdFluorescence imaging devices increase detection sensitivity starting at ~10^4 CFU/g (104 CFU/g)

Clinical concern thresholdsBacterial loads of concern discussed range from 10^4 to 10^9 CFU/g (104–109 CFU/g)

Peak diagnostic sensitivitySensitivity of fluorescence imaging peaked at 92.6% for loads >10^8 CFU/g

Prevalence in studied DFUsIn one analysis, 93.9% of diabetic foot ulcers had bacterial loads >10^4 CFU/g

Peri-wound involvementImaging showed 84.2% of ulcers contained high loads in the peri-wound region

Provider Requirements, Prior Authorization, and Documentation

Note

Ohio medical necessity evaluation — state-specific applicability

This Medical Policy applies only to the state of Ohio. Medical necessity evaluations will follow Ohio Administrative Code (OAC) requirements (OAC 5160-1-01) and any applicable federal or contractual plan rules. When evaluating requests for services described as unproven or subject to coverage limits, reference OAC and plan-specific benefit terms to determine medical necessity.

State-specific evaluation under Ohio Administrative Code (OAC 5160-1-01).
Reference federal, state (OAC), or contractual requirements where they differ; in a conflict, those requirements govern.

Prior Authorization

Prior authorization likely required for fluorescence imaging

Prior authorization may be required for fluorescence imaging and other services addressed in this policy. Because evidence for noncontact real-time fluorescence wound imaging (e.g., MolecuLight i:X) is inconclusive per ECRI and device utility is not established, seek prior authorization before performing these services when plan rules require it.

Therapy Descriptions and Context

Background: Noncontact normothermic wound therapy (NNWT) applies radiant heat and maintains a humid environment to raise wound temperature. Low-frequency ultrasound (for example, the MIST Therapy System) uses an ultrasonic handset to generate a saline mist and deliver ~40 kHz energy to the wound surface for cleansing/debridement and to potentially stimulate healing. Fluorescence wound imaging (for example, MolecuLight i:X) is a handheld, noncontact device that uses violet light to detect bacterial autofluorescence at shallow depths (approximately 1–1.5 mm) and may aid identification of wounds with higher bacterial loads. Evidence for these technologies is limited by small, observational or pilot studies, heterogeneity of methods, and a lack of adequately powered randomized controlled trials showing improved patient-centered outcomes.

Device and Term Definitions

NNWT — definition

DefinitionNoncontact normothermic wound therapy (NNWT) uses a noncontact wound cover and a warming unit to apply radiant heat and maintain 100% relative humidity to raise wound temperature and increase blood flow and oxygen to the wound.

Delivery methodApplied via a wound cover and warming unit; treatment is noncontact and maintains a humid environment

Intended effectIntended to increase local wound temperature to promote perfusion and healing

Low-frequency ultrasound / MIST Therapy — definition

DefinitionLow-frequency (noncontact) ultrasound (MIST Therapy) uses an ultrasonic handset to generate a saline mist that delivers low levels of ultrasonic energy (~40 kHz) to the wound surface.

Mechanism

Policy Revision History

2025-09-01RevisionLatest

Supporting Information: Clinical Evidence and References sections updated; previous policy version CS132OH.B archived.

Policy Summary

PayerUnitedHealthcare

PolicyNoncontact Warming Therapy, Ultrasound Therapy, and Fluorescence Imaging for Wounds (for Ohio Only)

Policy CodePolicy CS132OH.C

Change TypeSupporting information and references updated

Effective DateSep 1, 2025

Next Review DateN/A

Key ActionVerify plan-specific federal, state (Ohio Administrative Code), and contractual prior authorization requirements before submitting requests for these services.

SourceLink

On This Page

Fluorescence imaging CPT codes (e.g., 0598T, 0599T) should be checked against plan prior authorization lists.

When in doubt, submit a pre-service authorization with supporting clinical documentation.

Prior Authorization

Verify plan-specific prior authorization requirements

Verify plan-specific prior authorization and coverage requirements before applying this policy. Coverage determination must reference the member's federal, state (OAC), or contractual benefit plan terms; these terms may mandate coverage or impose additional requirements not reflected in this policy.

Check member contract, benefit plan documents, and any plan prior authorization portals.
If the benefit plan requires InterQual, ASAM, or other specific criteria, use those tools in conjunction with this policy.

Denial Risk

Denial triggers — unproven / not medically necessary

Denials may be issued for therapies considered unproven or not medically necessary. Examples include noncontact normothermic wound therapy (NNWT/warming therapy), low-frequency (noncontact) ultrasound therapies, and noncontact real-time fluorescence wound imaging when clinical evidence is insufficient to demonstrate safety and effectiveness.

Unproven / Not medically necessary: NNWT (warming therapy), low-frequency ultrasound (e.g., MIST/MIST Therapy System), and fluorescence imaging when evidence is insufficient.
Use applicable codes and documentation to justify medical necessity if requesting coverage despite limited evidence.

Denial Risk

Insufficient evidence may trigger denial

Insufficient or inconclusive evidence may trigger denial. For example, ECRI has concluded the evidence for MolecuLight i:X is inconclusive and additional RCTs are needed. Document the clinical rationale and any supporting evidence when requesting coverage for devices or therapies with limited or conflicting data.

ECRI assessment (2021; updated 2024) indicates insufficient evidence to determine improvement in patient outcomes for fluorescence imaging.
Pilot, observational, or underpowered RCTs (e.g., small RCTs or single-center pilots) are not sufficient alone to establish clinical utility.

Documentation Required

Coverage determination documentation

Coverage determinations must be documented with references to the applicable federal, state (OAC), or contractual benefit plan provisions. When deciding coverage, include citations to the member's plan language, relevant OAC sections, and any applicable clinical criteria (InterQual, ASAM, etc.).

Document the specific benefit language or OAC citation relied upon in the determination.
Include clinical justification and literature citations used to support approval or denial.

Documentation Required

Supporting clinical evidence required

Supporting clinical evidence must be provided for requests of services considered investigational or with limited data. Acceptable documentation includes randomized controlled trials, well-designed observational studies, and a clear rationale linking the intervention to improved patient-centered outcomes.

Provide trial-level evidence (RCTs preferred) and explain limitations of available studies (e.g., pilot, underpowered, observational).
Include details of prior standard wound care tried and clinical course to justify use as adjunctive therapy.

Note

Adjunctive use after standard care

Document that standard wound care has been attempted and optimized before considering adjunctive therapies. For wound therapies with mixed or limited results (e.g., ultrasound therapies), include prior use of standard treatments such as debridement, offloading, compression therapy, infection control, and appropriate dressings.

Record dates and details of standard care measures (debridement, offloading, compression, infection management) and response to those treatments.
Adjunctive therapies should be justified with objective measures (wound size trends, PAR) and clinical rationale.

Note

State/contractual coverage compliance required

Decisions must comply with federal, state (OAC), and contractual requirements. In the event of conflict between this policy and member-specific plan terms or state/federal law, applicable federal/state/contractual requirements govern. Always verify and cite the controlling requirement in the member's file.

When conflicts exist, federal, state (OAC), or contractual requirements take precedence over this policy.
Retain documentation showing how the controlling requirement was identified and applied.

Billing Rule

Coding and documentation notes

Coding and documentation notes: include applicable procedure and device codes for reference when preparing authorizations or claims. Listing of a code does not imply coverage. Provide clinical notes, prior treatment history, and supporting literature with authorization requests.

Reference codes (examples): 0598T, 0599T (fluorescence imaging); 97610 (low-frequency ultrasound wound treatment); HCPCS E0230–E0232/A6000 series for warming devices — inclusion does not imply coverage.
Ensure clinical records document the medical necessity rationale tied to member-specific benefits.

The transducer tip vibrates 40,000 times per second (40 kHz) producing ultrasound waves carried by saline mist to cleanse and debride wound surface and stimulate cellular activities.

Device components & useSystem includes ultrasound generator, handheld transducer, and single-use applicator with saline reservoir; handset is held ~1 cm from the wound during treatment.

Fluorescence wound imaging — definition

DefinitionNoncontact real-time fluorescence wound imaging is a handheld device using violet light illumination to detect and document bacterial fluorescence in wounds and surrounding areas to assist diagnostic and treatment decisions (example: MolecuLight i:Xe).

Clinical useProvides clinicians with fluorescence characteristics of a wound to guide debridement, sampling, and treatment targeting

OutputCaptures and documents fluorescent signals indicating presence and location of bacteria at point of care

CIBL — Chronic inhibitory bacterial load

DefinitionChronic inhibitory bacterial load (CIBL) refers to bacterial loads in wounds that are sufficient to inhibit healing and may warrant earlier intervention along the bacterial-infection continuum.

ContextCIBL concept is intended to encourage earlier assessment and management to prevent progression to clinical infection and support improved outcomes in DFUs.

Relation to thresholdsCIBL discussion is tied to bacterial load thresholds reported in studies evaluating loads from 10^4 to 10^9 CFU/g.

Fluorescence imaging — detection limits and limitations

Detection depthFluorescence imaging detects bacterial autofluorescence from the wound surface to a limited depth (~1.5 mm)

Limitations — organismsMay not detect bacteria that do not produce detectable porphyrin-derived fluorescence (non-porphyrin-producing organisms)

Clinical implicationPositive fluorescence signals correlate with high bacterial loads but absence of signal does not rule out deeper or non-fluorescent bacterial presence

MolecuLight i:X — device and regulatory status

Device and clearanceMolecuLight i:X is a handheld bacterial fluorescence imaging device cleared by the FDA via the 510(k) premarket notification process as substantially equivalent to predicate devices.

PurposeCleared for use to detect and document bacterial fluorescence in wounds to assist clinical assessment

Regulatory noteFDA clearance is informational and not a basis for coverage decisions

MIST Therapy System — device and regulatory status

Device classificationThe MIST Therapy System is regulated by the FDA as a Class II device and classified as an ultrasound wound cleaner.

510(k) clearanceThe MIST Therapy System was cleared via FDA 510(k) (approved indication: produce a low-energy ultrasound-generated mist to promote wound healing through cleansing and maintenance debridement by removing yellow slough, fibrin, exudates, and bacteria).

Intended effectsManufacturer describes effects as wound cleansing/debridement and stimulating healing via removal of slough, exudate, fibrin, and bacteria.