ModifiedUnitedHealthcarePolicy CS132OH.D

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

UnitedHealthcare medical policy governing coverage and medical necessity determinations for noncontact normothermic wound warming therapy, low-frequency ultrasound therapy (including MIST/MIST Therapy/MIST® and noncontact low-frequency ultrasound), and real-time fluorescence wound imaging in the state of Ohio; applies to requests evaluated under Ohio Administrative Code 5160-101.

Policy Summary

PayerUnitedHealthcare

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

Policy CodePolicy CS132OH.D

Change TypeRevised CPT descriptionsarchived prior version

Effective DateApr 1, 2026

Next Review Date

Key ActionVerify CPT code descriptions and prior authorization requirements for codes 0598T and 0599T with current payer rules before submitting requests.

SourceLink

POLICY UPDATE CHANGES

Revised description for CPT codes 0598T and 0599T.

Archived previous policy version CS132OH.C.

3modalities addressed

Ohiopolicy jurisdiction

Unprovencoverage stance

4example codes listed

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2026-04-01last revision

Coverage Criteria and Policy Stance

General coverage stance

Covered when ALL of the following are met

Default: No positive coverage criteria provided in this document section; warming therapy (NNWT), low-frequency ultrasound therapy, and noncontact real-time fluorescence wound imaging are stated as unproven and not medically necessary for treating wounds due to insufficient evidence of efficacy and/or safety.

Policy provides a negative coverage stance rather than specific qualification criteria.

Coverage stance — ultrasound and fluorescence imaging

Summary of coverage-relevant evidence and stance

Low-dose/high-frequency therapeutic ultrasound: Randomized evidence (Watson et al. 2011, n=337) of weekly low-dose, high-frequency ultrasound added to standard care showed no increase in ulcer healing rates, no difference in time to complete healing, no reduction in recurrence, and more adverse events in the ultrasound group; overall evidence for low-frequency ultrasound is mixed with small studies suggesting possible benefit for specific dosing regimens but is inconclusive for routine clinical benefit.

Higher-quality, adequately powered RCTs needed

Noncontact fluorescence wound imaging: Diagnostic accuracy and observational studies (including a multicenter prospective study of 350 participants) demonstrate increased sensitivity and accuracy for detecting moderate-to-heavy bacterial loads (detection beginning around 10^4 CFU/g) when fluorescence imaging is used alongside clinical signs and symptoms, but clinical utility for improving patient-centered outcomes (e.g., wound closure time, antibiotic stewardship) remains unproven; ECRI's assessment labels the evidence inconclusive and calls for additional RCTs.

Regulatory clearance (FDA 510[k]) is informational and does not establish clinical utility

Evidence-based coverage considerations

Coverage considerations and conditions based on available evidence and guideline positions

Diagnostic utility: Fluorescence imaging increases sensitivity and accuracy for detecting moderate-to-heavy bacterial loads compared with clinical signs alone in multiple observational and pilot studies; authors and assessments recommend using imaging in combination with clinical signs and symptoms (CSS) and confirmatory microbiology rather than as a standalone diagnostic or decision tool.evidence: observational and pilot studies; RCTs lacking

References include Le et al. (multicenter observational), Serena et al. (pilot) and ECRI assessment

Evidence gaps: Available evidence is insufficient to demonstrate improvement in patient-centered outcomes such as wound closure time or antibiotic stewardship; authoritative assessments (ECRI 2021/2024 update, NICE MIB212 2020) conclude the evidence is inconclusive and request additional randomized trials.ECRI 2021 (updated 2024); NICE MIB212 2020

FDA 510(k) clearance is informational and not sufficient for coverage decisions

UnitedHealthcare considers noncontact normothermic wound therapy (NNWT), low-frequency ultrasound (LF-US), and noncontact real-time fluorescence wound imaging to be unproven and not medically necessary for treating wounds due to insufficient evidence of efficacy and/or safety. The policy provides a negative coverage stance rather than conditions that would support routine coverage.

Procedures and devices without adequate published evidence of safety and effectiveness may be considered experimental or investigational. For fluorescence wound imaging specifically, diagnostic accuracy studies exist but the clinical utility of the method to improve patient-centered outcomes remains unclear; additional randomized controlled trials are needed to validate safety and efficacy before routine coverage can be supported.

Regulatory status (e.g., FDA 510(k) clearance) is provided for informational context only and, by itself, does not establish medical necessity or guarantee coverage. Devices mentioned in this policy (for example, MolecuLight i:X, MIST Therapy®, and warming devices) have received FDA clearance via 510(k), but such clearance is not sufficient to determine coverage.

Coverage determinations must reference applicable federal, state (including the Ohio Administrative Code), and contractual benefit requirements. In the event of a conflict, federal, state (OAC), or contractual terms govern; providers should verify those requirements before relying on this policy.

UnitedHealthcare explicitly states that NNWT and low-frequency ultrasound therapy are considered unproven and not medically necessary for treating wounds based on insufficient evidence of efficacy.

A large randomized controlled trial (Watson et al., 2011; n = 337) evaluating weekly, low-dose, high-frequency therapeutic ultrasound plus standard care versus standard care alone for hard-to-heal venous leg ulcers found no significant difference in time to healing, complete healing, recurrence rates, or health-related quality of life, and reported more adverse events in the ultrasound group. Based on these results, weekly low-dose, high-frequency ultrasound did not increase healing rates or reduce recurrence.

Use of the MolecuLight i:X fluorescence imaging device as a stand‑alone tool to change management or improve patient-centered outcomes is considered unproven and inconclusive. Clinical evidence assessments (ECRI, updated 2024) conclude that current studies are insufficient to demonstrate improvements in patient outcomes despite diagnostic sensitivity for elevated bacterial loads.

No explicit additional conditions that would render these services not medically necessary are provided beyond the general statements in this policy excerpt. Review of federal, state (OAC), or contractual benefit terms is required for case-specific determinations.

Procedure and Device Coding

Procedure / CPT (reference)CPT

0598T	Real-time fluorescence wound imaging with clinical darkness, to identify location of bacterial wound pathogens and measure wound size, per session; first anatomic site (e.g., lower extremity, right leg).
0599T	Real-time fluorescence wound imaging with clinical darkness, to identify location of bacterial wound pathogens and measure wound size, per session; each additional anatomic site (e.g., upper extremity, left leg) (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

HCPCS device/supply codes (reference)HCPCS

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

Applicable CPT codes (mentioned in Policy History)CPT

0598T	Revised description referenced in policy history
0599T	Revised description referenced in policy history

Applicable CPT Codes (revised descriptions)CPT

0598T	Revised description (as noted in policy history)
0599T	Revised description (as noted in policy history)

inv-16: Bacterial load thresholds — fluorescence device detection and microbiology thresholds

Fluorescence detection thresholdFluorescence imaging (MolecuLight) can detect bacterial loads starting at approximately 10^4 CFU/g

Common microbiology thresholdMicrobiology culture thresholds used in studies and clinical practice often cite 10^5 CFU/g as a level of concern

Peak sensitivity at high loadsFL-imaging sensitivity peaks (reported 92.6%) for loads >10^8 CFU/g in DFU analysis

Clinical implicationImaging can identify peri-wound high loads (e.g., 84.2% peri-wound involvement reported), enabling targeted sampling and debridement

Provider Actions, Prior Authorization, and Documentation

Prior Authorization

Prior Authorization and Coding

Verify CPT code descriptions and prior authorization requirements with current payer and coding resources. Inclusion of codes in this policy is for reference only and does not guarantee coverage; benefit determinations are subject to federal, state (Ohio Administrative Code 5160-101), or contractual terms.

Check CPT descriptions for 0598T and 0599T (revised 2026-04-01) and any payer-specific PA rules
Confirm whether services (e.g., 97610, A6000, E0231, E0232) require prior authorization under the member's plan
Listing of a code does not imply coverage or reimbursement rights

Note

Regulatory Status Is Informational

FDA clearance or 510(k) status is informational and does not by itself establish medical necessity or guarantee coverage. Coverage decisions must follow federal, state (OAC) or contractual benefit requirements.

Examples: MolecuLight i:X has 510(k) clearance but evidence for clinical utility is inconclusive

Background and Evidence Summary

Noncontact normothermic wound therapy (NNWT) uses a noncontact wound cover and a warming unit to apply radiant heat and maintain humidity with the intent of increasing wound temperature, blood flow, and oxygenation to promote healing. Although described in the literature as a modality to modulate local wound environment, the evidence supporting clinically meaningful improvements in healing outcomes is inadequate.

Definitions and Key Terms

inv-34: NNWT — definition/key-value entry

DefinitionNoncontact normothermic wound therapy (NNWT) uses 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

Intended effectAims to improve wound perfusion and oxygenation to promote healing

ComponentsConsists of a warming unit, warming card, and noncontact wound cover (HCPCS codes A6000, E0231, E0232 referenced)

inv-35: Low-frequency ultrasound — definition/key-value entry (MIST Therapy® / noncontact LF-US)

DefinitionLow-frequency (low-energy) ultrasound delivers ultrasonic energy via a saline mist (MIST Therapy®) in a noncontact manner to cleanse, debride, and stimulate wound healing

Device operation

Revision History and Policy Changes

2026-04-01code_description_revisionLatest

Revised CPT code descriptions for 0598T and 0599T; supporting information notes archival of previous policy version CS132OH.C.

Policy Summary

PayerUnitedHealthcare

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

Policy CodePolicy CS132OH.D

Change TypeRevised CPT descriptionsarchived prior version

Effective DateApr 1, 2026

Next Review Date

Key ActionVerify CPT code descriptions and prior authorization requirements for codes 0598T and 0599T with current payer rules before submitting requests.

SourceLink

On This Page

Adjunctive therapy positioning: Guidelines (AAWC, NICE) consider low-frequency ultrasound and other adjunctive modalities as potential options only in combination with standard care (e.g., compression for venous ulcers, offloading for DFUs, debridement, dressings) and note limited evidence for routine adoption; warming therapy is noted to have insufficient evidence to inform routine use.guideline-based

AAWC 2015; NICE guidance (MIST Therapy and DFU management) emphasize standard care first and limited evidence for adjunctive devices

Verify governing benefit terms before approving services

Documentation Required