ModifiedUnitedHealthcarePolicy CS132KY.06

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

Medical policy governing use of noncontact normothermic wound warming, low-frequency ultrasound (including MIST/NLFU) and noncontact fluorescence imaging for bacterial detection in wounds — applies to Kentucky providers and members.

Policy Summary

PayerUnitedHealthcare

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

Policy CodePolicy CS132KY.06

Change TypeClinical evidence and references updated

Effective DateAugust 1, 2025

Next Review DateN/A

Key ActionDocument prior use of standard wound care (compression, dressing changes) and provide supporting clinical documentation if requesting authorization for adjunctive ultrasound or fluorescence imaging.

SourceLink

POLICY UPDATE CHANGES

Updated Clinical Evidence and References sections to reflect the most current information

3technologies addressed

Kentuckystate applicability

insufficient evidencecoverage rationale

0598T, 0599T, 97610referenced codes

CS132KY.05

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

Coverage Determinations

Not medically necessary - primary stance

Coverage determinations:

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

Limitations of existing studies include small sample sizes, lack of controls or randomization, and short follow-up; systematic reviews found no RCTs establishing benefit.

Low-frequency ultrasound therapy (contact or noncontact, including MIST/NLFU) is considered unproven and not medically necessary due to insufficient evidence of efficacy.

Available studies lack adequate sample sizes and proper control groups; further well-controlled trials with larger samples are needed to demonstrate clinical benefit.

Noncontact fluorescence wound imaging: Noncontact real-time fluorescence wound imaging for bacterial presence (e.g., MolecuLight i:X) is considered unproven and not medically necessary due to insufficient evidence of safety and/or efficacy.

Evidence is inconclusive and insufficient to demonstrate improvement in patient-centered outcomes; assessments (e.g., ECRI, NICE) describe limited or inconclusive data.

This policy applies to services provided to members in Kentucky. Warming therapy (noncontact normothermic wound therapy), low-frequency ultrasound therapy (including MIST/NLFU), and noncontact real-time fluorescence wound imaging for bacterial presence are considered unproven and not medically necessary for the treatment of wounds due to insufficient evidence of efficacy.

A clinical evidence assessment by ECRI concluded that the evidence for the MolecuLight i:X Fluorescence Imaging System is inconclusive. Available studies do not provide sufficient evidence to determine whether use of the device improves patient-centered outcomes; additional randomized controlled trials are needed to confirm safety and efficacy.

Overall, the evidence is insufficient to conclude that the MolecuLight i:X fluorescence imaging system or MIST/low-frequency ultrasound therapy reliably improves patient-centered outcomes or supports routine adoption. Both ECRI and NICE describe the existing data as limited or inconclusive and call for higher-quality randomized trials before routine coverage can be recommended.

This Medical Policy is provided for informational purposes to assist in interpreting UnitedHealthcare standard benefit plans. It is not medical advice and must be used in conjunction with the applicable federal, state, or contractual benefit plan terms and the independent clinical judgment of treating providers; in the event of conflict, federal, state, or contractual requirements govern coverage decisions.

Explicitly considered unproven and not medically necessary under this policy are: warming therapy (noncontact normothermic wound therapy, NNWT), low-frequency ultrasound therapy (including MIST/NLFU), and noncontact real-time fluorescence wound imaging for detection of bacterial presence.

In a multicenter randomized controlled trial (Watson et al., 2011) of 337 participants with hard-to-heal venous leg ulcers, weekly low-dose, high-frequency therapeutic ultrasound given for up to 12 weeks in addition to standard care showed no significant difference in time to healing of the reference ulcer or in time to complete healing of all ulcers compared with standard care alone. There were no differences in recurrence rates or health-related quality of life, and the ultrasound group experienced a higher number of adverse events.

Routine use of the MolecuLight i:X device is not supported by the current limited evidence for improving wound closure times or for antibiotic stewardship. ECRI characterizes available evidence as inconclusive, and NICE’s Medtech briefing noted limited evidence that the device reduces wound closure time or improves antibiotic stewardship, indicating that clinical benefit for routine use has not been established.

Procedure, CPT and Supply Codes Referenced

Covered/Referenced CPT CodesCPT

0598T	Noncontact real-time fluorescence wound imaging, for bacterial presence, location, and load, per session; first anatomic site (e.g., lower extremity).
0599T	Noncontact real-time fluorescence wound imaging, for bacterial presence, location, and load, per session; each additional anatomic site (e.g., upper extremity) (List separately in addition to code for primary procedure).
97610	Low frequency, non-contact, non-thermal ultrasound, including topical application(s), when performed, wound assessment, and instruction(s) for ongoing care, per day.

Referenced HCPCS/Supply CodesHCPCS

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 detection thresholds

Device detection thresholdFluorescence imaging (MolecuLight) detects bacteria starting at approximately 10^4 CFU/g in tissue specimens

Microbiology comparison threshold (some studies)Some study comparisons use a microbiology threshold of 10^5 CFU/g when categorizing high bacterial loads

Range evaluated in trialsStudies comparing clinical assessment and fluorescence imaging evaluated bacterial loads across ~10^4 to 10^9 CFU/g

Provider Requirements, Prior Authorization and Documentation

Prior Authorization

Prior authorization recommended

Prior authorization is recommended when the evidence is inconclusive for a technology or device (for example, when ECRI or other assessments report insufficient or inconclusive evidence). Providers should check plan-specific prior authorization rules before scheduling services.

Prior authorization may be requested for adjunctive diagnostics or therapies when clinical benefit is not well established.
Prior authorization does not guarantee coverage; benefit determination is based on federal, state, or contractual requirements.

Denial Risk

Evidence insufficiency may trigger coverage denial

Insufficient or inconclusive evidence for a device or therapy (for example, low-frequency ultrasound, noncontact warming, or fluorescence imaging when evidence is lacking) may lead to a determination that the service is not medically necessary and result in claim denial. Providers should ensure conservative documentation supporting medical necessity is available.

Clinical Background and Rationale

Noncontact normothermic wound therapy (NNWT) applies radiant heat and humidity to the wound using a noncontact wound cover and warming unit to raise local tissue temperature. The intended mechanisms include increasing local blood flow and oxygen delivery to the wound bed, which may theoretically support healing, but current clinical evidence is insufficient to demonstrate consistent patient benefit.

Key Definitions

Warming therapy (Noncontact normothermic wound therapy, NNWT)

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

IntentRaise wound temperature and humidity to promote perfusion and oxygenation of chronic wounds

ComponentsNoncontact wound cover, warming unit, and warming card/wound cover supplies (device and consumables described in coding section)

Low-frequency ultrasound (MIST/NLFU)

DefinitionLow-frequency ultrasound (MIST/NLFU) delivers low-frequency (~40 kHz) ultrasonic energy via a saline mist or applicator to the wound to provide simultaneous cleansing, debridement, and potential stimulation of healing

Policy Change Log

08/01/2025revisedLatest

Updated Clinical Evidence and References sections; archived previous policy version CS132KY.05.

Policy Summary

PayerUnitedHealthcare

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

Policy CodePolicy CS132KY.06

Change TypeClinical evidence and references updated

Effective DateAugust 1, 2025

Next Review DateN/A

SourceLink

On This Page

Therapies considered unproven and not medically necessary may be denied.
Evidence gaps identified in clinical reviews can be a basis for denial decisions.

Note

FDA informational note

FDA 510(k) clearance or other FDA statements are provided for informational purposes only. FDA clearance alone is not a basis for coverage or reimbursement decisions under this policy.

Examples: Warm-Up Active Wound Therapy, MIST Therapy System, MolecuLight i:X — FDA status noted for information only.

Note

Conflict with plan or regulatory requirements

When there is a conflict between this policy and federal, state, or contract terms, the applicable federal, state, or contractual requirements govern. Verify member benefits and plan documents for coverage rules that may supersede this policy.

Always defer to the member’s contract, state mandates, and applicable laws.
Contact the plan or utilization management vendor (e.g., InterQual®) for case-specific determinations.

Billing Rule

Coding and documentation note

Listing of procedure, supply, or diagnosis codes in this policy is for reference only and does not imply coverage or reimbursement. Providers must submit appropriate codes and supporting documentation; inclusion in this policy does not guarantee payment.

Reference codes include (not all inclusive): 0598T, 0599T, 97610, A6000, E0231, E0232.
Inclusion of a code does not imply coverage; verify coding guidance and claim edits with the payer.

Documentation Required

Coverage decision documentation

When making coverage determinations, document the clinical rationale and reference governing criteria. Use InterQual® criteria as the primary source when applicable and attach medical necessity documentation to the prior authorization or claim.

Document: wound history, prior therapies tried, wound measurements (size, area), imaging and microbiology results, and clinical signs and symptoms (CSS).
If InterQual® is not applicable, reference UnitedHealthcare medical policies, Coverage Determination Guidelines, and/or contract terms.

Step Therapy

Step through standard wound care before adjunctive ultrasound

Step through and document standard wound care measures before using adjunctive ultrasound or other adjunctive therapies. Document prior and concurrent use of compression therapy, moisture-retentive dressings, offloading (for DFUs), wound debridement, infection control, and optimization of ischemia as appropriate.

Record dates and duration of prior standard therapies (e.g., compression, dressings, offloading).
Document response (or lack of response) to standard care prior to initiating adjunctive therapy.

Note

Adjunctive therapy positioning

Adjunctive therapies (ultrasound stimulation, warming devices, fluorescence imaging) should be considered as adjuncts to — not substitutes for — standard, guideline-directed wound care. Use adjunctive modalities to support, not replace, patient-appropriate compression, dressings, debridement, and other standard treatments.

Consider adjunctive therapy only after documenting inadequate response to first-line measures.
When used, combine ultrasound with adequate compression and moisture-retentive dressings as recommended by guidelines.

Handheld ultrasonic transducer held approximately 1 cm from wound with sterile saline in a disposable applicator reservoir (MIST Therapy System)

Proposed effectsRemoves slough/exudate/bacteria from wound surface and may stimulate angiogenesis and growth factor production to aid healing

Noncontact fluorescence wound imaging (handheld device, e.g., MolecuLight i:X)

DefinitionHandheld noncontact fluorescence imaging device (e.g., MolecuLight i:X) that uses violet light illumination to capture real-time fluorescent signals from bacteria in wounds to assist localization and clinical decision-making

FunctionProvides clinicians images of fluorescent characteristics of wound and surrounding tissue to guide targeted debridement or sampling

Clinical contextReported to increase sensitivity and accuracy for detecting moderate-to-heavy bacterial loads when used with clinical assessment, but evidence for patient-centered outcome improvement is inconclusive

Fluorescence imaging device specifics and detection thresholds

Device specificsMolecuLight i:X is a handheld, noncontact system using violet light to visualize bacterial fluorescence and localize areas of high bacterial load

Detection sensitivity reportedStudies report high sensitivity for loads ≥10^4 CFU/g (e.g., Armstrong et al. found most wounds had >10^4 CFU/g; Mayer et al. report fluorescence sensitivity 84% vs SEM/PCR)

Limitations notedAlthough fluorescence imaging improves detection of bacterial loads versus CSS alone, systematic assessments (ECRI) find evidence inconclusive for improvement in patient outcomes

Noncontact low-frequency ultrasound variants and intent (NCLF-US / USSD)

DefinitionNoncontact low-frequency ultrasound (NCLF-US / USSD) refers to therapeutic ultrasound delivered at low frequency (around 20–40 kHz) or low dose, often delivered via a saline mist or as noncontact airborne application to promote wound healing

Variants/SystemsIncludes MIST Therapy System (saline mist, ~40 kHz), and other noncontact airborne low-frequency ultrasound devices evaluated in trials

Intended useIntended as an adjunct to standard wound care to cleanse/debride wounds and stimulate healing, with varying schedules (e.g., thrice weekly vs once weekly) studied

CSS (clinical signs and symptoms) assessment

DefinitionClinical signs and symptoms (CSS) assessment uses bedside evaluation (e.g., NERDS/STONEES, wound appearance, exudate, erythema, temperature, pain) to identify possible infection or moderate-to-heavy bacterial burden

RoleCSS is recommended to be documented when fluorescence imaging is used; CSS alone may miss many wounds with elevated bacterial loads

Use with imagingGuidance in studies recommends combining CSS assessment with fluorescence imaging for improved diagnostic sensitivity

NERDS / STONEES clinical checklists for infection assessment

NERDS checklistNERDS (non-healing, exudate, red and bleeding surface or granulation tissue, debris, smell) is used to identify wounds with concerns for moderate-to-heavy bacterial load

STONEES checklistSTONEES (size, temperature, osteomyelitis, new areas, exudate, erythema, smell) is used alongside NERDS to evaluate wounds for infection-related features

Clinical purposeThese checklists are employed in diagnostic accuracy studies to compare bedside CSS with fluorescence imaging and microbiology

Noncontact low-frequency ultrasound summary (20-40 kHz) as evaluated in RCTs

Definition and frequencyNoncontact low-frequency ultrasound used in clinical trials is typically in the 20–40 kHz range and has been evaluated as an adjunctive therapy in multiple randomized controlled trials and systematic reviews

Evidence summarySystematic review/meta-analysis (Voigt et al. 2011) and multiple RCTs from 2011–2019 evaluated NCLF-US; results are heterogeneous and limited by study quality and size

Typical intent in RCTsStudied as adjunct to standard care (e.g., compression, dressings) to assess effects on wound healing, pain, edema, and recurrence

Local warming / radiant heat therapy modalities studied for chronic wounds

Modalities studiedLocal warming and radiant heat therapies studied include radiant heat bandages and noncontact warming devices applied to venous leg ulcers and pressure ulcers

PurposeIntended to raise local wound temperature to improve perfusion and oxygenation and thereby support chronic wound healing

Evidence baseEvidence consists of small pilot and controlled studies (e.g., Thomas et al. 2005 and systematic reviews) with limited sample sizes and mixed results