The healthcare system uses standardized Current Procedural Terminology (CPT) codes to describe medical procedures, ensuring services are recognized and billed consistently across the country. CPT 93971 identifies a specialized vascular ultrasound procedure related to bypass surgery. This test provides detailed imaging of blood flow within the vessels, playing an important role in the long-term management of patients who have undergone vascular repair.
Defining the Duplex Scan CPT 93971
CPT 93971 specifically describes a “Duplex scan of extremity veins including responses to compression and other maneuvers; unilateral or limited study.” A duplex scan is a non-invasive imaging method that combines B-mode ultrasound, which images the vessel structure, with Doppler ultrasound, which assesses the velocity and direction of blood flow. This combination allows for both structural imaging and blood flow analysis. The code 93971 is used when the study is performed on the veins of a single limb or when the examination is limited in scope. This procedure is frequently used to evaluate potential harvest vein grafts before bypass surgery. The complete version of this test, performed on both extremities, is covered by the separate code, 93970.
Medical Reasons for Performing the Scan
The primary purpose of a duplex scan is to monitor the health and performance of arterial bypass grafts after vascular surgery. Grafts are placed to reroute blood around a blocked artery, and regular surveillance using CPT 93971 is a standard part of post-operative care to ensure the graft remains patent.
This scan is effective at detecting stenosis, a narrowing that significantly impedes blood flow. By measuring blood flow speed, the test identifies areas where velocity is abnormally high, indicating a narrowing or blockage. Surveillance protocols often recommend scans at frequent intervals following surgery, such as at three, six, and twelve months, and then annually if the graft remains healthy. Early detection allows for timely intervention, such as angioplasty or revision surgery, increasing the chance of long-term graft survival. The scan also checks for the formation of a thrombus (blood clot) or aneurysmal dilatation.
Preparing for and Undergoing the Procedure
Patients typically require minimal preparation for this non-invasive duplex scan. For scans of limb bypass grafts, no fasting is usually necessary, and patients can take all their regular medications as scheduled. If the graft is located in the abdomen, however, the patient may be asked to fast for about six hours to minimize bowel gas, which can interfere with image clarity.
During the procedure, the patient lies comfortably while a technician applies a water-soluble gel to the skin over the bypass graft. The probe is gently moved along the path of the graft, capturing images of the vessel and measuring blood flow. The procedure is painless, although the patient may hear a characteristic “swooshing” sound from the Doppler signals. The entire examination typically takes between 20 and 60 minutes, depending on the complexity and location of the graft.
How This Code Affects Billing and Insurance
CPT 93971 is the administrative mechanism for billing the duplex scan service to insurance providers. When a medical facility or physician performs this procedure, they submit this code on the claim form to describe the exact service rendered. The code is associated with a specific fee used by the insurance company, including Medicare, to determine coverage and reimbursement.
The total cost is generally divided into two components. The technical component covers the equipment, supplies, and technologist’s time, while the professional component covers the physician’s fee for interpreting the images and writing the diagnostic report. Proper use of the code ensures the service meets the medical necessity requirements of the payer, which is essential for accurate processing and to avoid claim denials.