Reimbursement and Coding Considerations for the TM-Flow System

The TM-Flow System from HealthWright Technologies gives independent practices a way to perform vascular, autonomic, and sudomotor testing in a single 7 to 10 minute visit.

The financial side matters as much as the clinical side: most TM-Flow tests are linked to established CPT codes that Medicare may reimburse when the testing is medically necessary and documented. A properly documented testing program supports the evaluation of symptomatic and at-risk patients while keeping each claim defensible on audit.

For a code-by-code look at how one CMAT device visit can support multiple billable services, see how a CMAT device visit maps to multiple CPT codes.

This page walks through the TM-Flow reimbursement landscape: which CPT codes apply, how Medicare rates are determined, what documentation triggers denials, and how to plan capacity for your specific clinic. For broader billing context, see our ABI CPT code guide and the CMAT encounter coding overview.

Which CPT Codes Apply to TM-Flow Testing?

The TM-Flow System bundles three distinct physiologic measurements into a single device. Each measurement maps to a separate CPT code, which is why each component may be separately billable when it is performed, interpreted, and medically necessary.

• CPT 93923 — Complete bilateral non-invasive physiologic studies of upper or lower extremity arteries at three or more levels (the ABI/TBI/PVR vascular component).
• CPT 95921 — Testing of autonomic nervous system function; cardiovagal innervation (parasympathetic function), including 2 or more of the following: heart rate response to deep breathing with recorded R-R interval, Valsalva ratio, and 30:15 ratio.
• CPT 95923 — Testing of autonomic nervous system function; sudomotor, including quantitative sudomotor axon reflex test (QSART), silastic sweat imprint, thermoregulatory sweat test, or changes in sympathetic skin potential.

For a deeper look at the autonomic component, see our autonomic nervous system testing methods and HRV testing guides.

How Is Medicare Reimbursement Determined for TM-Flow CPT Codes?

Medicare reimbursement is calculated by multiplying each CPT code’s relative value units (RVUs) by the annual conversion factor set in the Medicare Physician Fee Schedule. Rates change each year and vary by geographic locality, so exact amounts should always be verified using the CMS PFS Look-up Tool for your region.

Coverage and payment for these codes are set by the applicable Medicare local coverage determination and require documented medical necessity. Confirm current rules and rates with your Medicare Administrative Contractor rather than relying on national averages.

Can All Three TM-Flow CPT Codes Be Billed in One Visit?

The clinical value of TM-Flow comes from running all three measurements together when each is clinically indicated. When 93923, 95921, and 95923 are performed and interpreted on the same date of service with proper documentation, each code is billed separately because each reflects a distinct physiologic test that is medically necessary in its own right.

Whether all three are billed in a given visit depends on the clinical indication for each test, the payer’s policies, and the documentation supporting medical necessity — not on a fixed protocol. For a full breakdown of how the three codes map to one encounter, review the CMAT encounter coding overview.

What Is the Documentation Required for a Clean Claim?

A clean claim for each CPT code in the TM-Flow battery typically requires:

• Medical necessity — documented risk factors (diabetes, hypertension, peripheral arterial disease symptoms, autonomic dysfunction symptoms, neuropathy, prior cardiovascular events) that justify each test ordered.
• Test indication — the clinical question the test is intended to answer, recorded in the order and the encounter note.
• Test performance details — date, equipment used, and confirmation that the protocol for the billed CPT code was followed.
• Physician interpretation and report — a signed interpretation, not just the device-generated printout. CPT 95921 and 95923 specifically require physician interpretation.
• Diagnostic linkage — the ICD-10 codes on the claim must match the documented indication and support the necessity of each CPT code billed.
• Retention — keep the device-generated report, interpretation, and order for the period required by your payer contracts and state law.

Medicare coverage of TM-Flow testing is governed by your Medicare Administrative Contractor’s local coverage determination, which sets frequency limits under medical-necessity indications, with more frequent testing allowed when symptoms or treatment changes justify it. Verify frequency limits and prior authorization requirements with each plan in your payer mix.

How Do You Plan TM-Flow Capacity and Workflow?

Planning a TM-Flow program starts with three honest numbers: your Medicare share, the share of your patients for whom testing is clinically indicated, and your realistic test volume per week.

Weekly test volume depends on the size of your patient population with a documented clinical indication for testing, and on how testing is scheduled within your existing visit workflow.

Account for the operational costs:

• staff time for the 7 to 10 minute test plus another 5-10 minutes for setup and patient instruction
• physician interpretation time (typically 3-5 minutes per report)
• disposables (electrodes, sensors)

Building these into your scheduling keeps the program sustainable and the documentation consistent across operators.

For a complete view of the business case (including device cost, training, payer credentialing, and implementation), contact HealthWright Technologies directly. HealthWright Technologies provides the TM-Flow System with training, billing support, and ongoing implementation help — see our CMAT Advantage vs standard ABI testing comparison for context on the full package.

How Do You Avoid Common Coding and Compliance Errors?

The most common TM-Flow billing errors are avoidable with workflow discipline:

• Duplicate or bundled coding — do not report a second extremity physiologic study for the same anatomic site on the same date; each TM-Flow CPT code reflects a distinct test, not the same test billed twice.
• Missing physician interpretation — the device printout alone is not an interpretation. CPT 95921 and 95923 require a signed physician report.
• Inadequate supervision documentation — when a clinical staff member performs the test, the supervising physician’s presence (general, direct, or personal as required by code) must be documented per CMS rules.
• Frequency overuse — exceeding the payer’s frequency limit without a documented medical indication change triggers denials and audit risk.
• Mismatched ICD-10 — ordering a test for one indication and submitting ICD-10 codes that don’t match is a fast path to denial.

Establish audit logs and a periodic chart review for each TM-Flow CPT code billed. For a related practice management view, see our physician dispensing program overview, which covers the same compliance discipline applied to in-office medication dispensing.

Frequently Asked Questions About TM-Flow Reimbursement

Are the TM-Flow CPT codes bundled together?

No. CPT 93923, 95921, and 95923 each reflect a distinct test and are billed separately when each is performed and interpreted on the same date of service. They are not part of a bundled code set under CMS NCCI edits when performed together as the TM-Flow battery.

Can a clinic bill all three TM-Flow CPT codes on the same day?

Yes, provided each test is independently performed, separately interpreted by the supervising physician, and supported by appropriate medical necessity documentation. Same-day billing is appropriate when each test is clinically indicated for the patient.

What is the typical frequency limit for TM-Flow testing?

Frequency limits for medically-indicated testing are set by your Medicare Administrative Contractor’s local coverage determination and vary by contractor. More frequent testing is generally allowed when documented symptoms, treatment changes, or follow-up of an abnormal prior finding justify it. Always verify frequency limits with your MAC.

Can a nurse practitioner or PA bill TM-Flow CPT codes?

Yes, subject to payer-specific rules. Nurse practitioners and physician assistants may bill CPT 93923 under their own NPI at 85% of the physician fee schedule. Because 95921 and 95923 require a signed physician interpretation and report, verify with your MAC before assigning those two codes to a non-physician practitioner. Note that these are diagnostic tests, and diagnostic tests are not billed incident to a physician’s service: they have their own Medicare benefit category and follow the supervision rules at 42 CFR 410.32 rather than the incident-to rules at 42 CFR 410.26. Confirm the supervision indicator for each code before you finalize a staffing plan.

Does telehealth qualify for TM-Flow billing?

No. TM-Flow requires in-person physiologic testing because the device must be physically connected to the patient (chest, wrist, ankle, and palmar/plantar electrodes). The interpretation can be performed off-site, but the test itself cannot be billed via telehealth modifiers.

Ready to Add TM-Flow to Your Practice?

The TM-Flow System turns 7 to 10 minutes of physiologic testing into actionable clinical insight and a documented, payer-recognized service. Reimbursement varies by payer mix, locality, and contract — but a properly implemented TM-Flow program is one of the few diagnostic additions that supports both patient care and a defensible, well-documented service line in primary care, cardiology, and metabolic clinics.

Comparing options for your practice? Work through our TM-Flow buyer’s checklist to vet accuracy data, payer coverage, and financing before you decide.

To discuss device pricing, the CMAT Advantage bundle, training, and implementation timelines for your practice, contact HealthWright Technologies at contact@healthwrighttechnologies.com or (678) 322-7146. Our office is located at 60 Bear Creek Marina Road, Mansfield, GA 30055. Learn more on the products page or our contact page.

Disclaimer: Reimbursement amounts and coverage policies vary by payer, region, and clinical indication. The information on this page is for general informational purposes only and does not constitute financial, billing, or legal advice. Providers are responsible for verifying coverage, coding accuracy, frequency limits, and compliance with all applicable federal, state, and payer requirements. HealthWright Technologies does not guarantee any specific reimbursement amounts or financial outcomes. CPT® is a registered trademark of the American Medical Association.