Duplex Scans – A Closer Look at 2020’s New Codes

Duplex scans are a common area of confusion across the country, and 2020 saw the introduction of two new codes for duplex scans, making for a potentially tricky start to the new year. Before we dive in to the new codes, let’s review some general guidelines for noninvasive vascular diagnostic studies.

Noninvasive vascular studies include patient care required to perform the studies. This is the usual pre-procedure work that is bundled into the study performed.

Noninvasive vascular studies include supervision of the study and interpretation of the study result. As with any imaging study, the radiologist must provide an interpretation of the results.

Noninvasive vascular studies require a hard-copy output, with analysis, of all data including bidirectional vascular flow or imaging when provided. The use of a simple hand-held or other Doppler device that does not produce hard copy output, or that produces a record that does not permit analysis of bidirectional vascular flow, is considered to be part of the physical examination of the vascular system and is not separately reported.

Use of color Doppler for anatomic structure identification only, in conjunction with a real-time ultrasound exam, is not reported separately. True vascular analysis must be performed— the use of Doppler simply to determine whether or not a structure is vascular does not constitute true vascular analysis. A full and complete color duplex with waveform analysis must be performed.

A duplex scan characterizes the pattern and direction of blood flow in arteries or veins and produces real-time images integrating B-mode two-dimensional vascular structure, Doppler spectral analysis and color flow Doppler imaging. In the Ultrasound Coding User’s Guide, the ACR specificallystates, “Assessing flow with color, recording a waveform and reporting thefindings in a medically indicated examination are the key elements to lookfor in a report.” In the report you should see documentation of the velocitymeasurements of blood flow, or you might see phrases such as “waveformnormal,” “spectral Doppler showed no flow” or “normal triphasic waveformpatterns using Doppler interrogation” to assign the duplex study codes.

What are the New Codes?

93985    Duplex scan of arterial inflow and venous outflow for preoperative vessel assessment prior to creation of hemodialysis access; complete bilateral study

93986    Duplex scan of arterial inflow and venous outflow for preoperative vessel assessment prior to creation of hemodialysis access; complete unilateral study

These codes describe a unilateral or bilateral scan (of either upper or lower extremity[ies]) performed prior to the construction of a hemodialysis access graft, where the arteries and veins are ultrasonically evaluated to determine the adequacy of the vessels for graft formation.

• These codes are not to be used for an arterial-venous duplex scan evaluating an existing graft, for an existing graft code 93990 should be reported instead.

These complete studies include both arterial inflow and venous outflow evaluation. Other code choices exist for scans evaluating only arterial inflow or only venous outflow as illustrated below:

As you can see, proper application of these new codes (as with all duplex scans) requires a careful examination of the documentation to ensure all required components are in the report. They are very specific in that they are for assessment prior to creation of a dialysis access and must include both arterial inflow and venous outflow. If the report does not meet these criteria, these codes should not be assigned.

As a reminder, both spectral analysis and color flow must be documented to assign any duplex codes, and the report should document the velocity measurements of blood flow. Several terms that indicate spectral analysis are: acceleration rate, monophasic, biphasic or triphasic waveforms, peak systolic velocity, resistive index (RI), velocity, waveform analysis.

Guidance with Noninvasive Vascular Studies, Diagnostic Ultrasound and Other Ultrasound Services

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