CPT® Code 76820

The CPT® Code 76820 refers to the procedure known as Doppler velocimetry, specifically focusing on the umbilical artery. This diagnostic test is performed by a physician to assess the blood flow velocity within the umbilical artery of a fetus. The primary purpose of this procedure is to aid in determining the optimal timing for labor induction and to diagnose or evaluate conditions such as fetal anemia. During the procedure, the mother is typically positioned in a semi-recumbent posture with a slight lateral tilt. This positioning is crucial as it helps to reduce the risk of supine hypotension syndrome, a condition that can occur when a pregnant woman lies flat on her back. To initiate the test, an acoustic coupling gel is applied to the skin of the lower abdomen, which enhances the transmission of sound waves. A transducer is then placed against the lower abdomen, and the physician manipulates it to capture Doppler frequency shift waveforms from the umbilical artery. The assessment of umbilical artery blood flow is conducted using either continuous wave or pulsed wave Doppler interrogation techniques, which evaluate the downstream impedance of the blood flow. The resulting Doppler waveforms are displayed on a video monitor, allowing for real-time visualization of the blood flow dynamics. When appropriate signals are identified, the screen is frozen to facilitate accurate measurements. These measurements are critical as they are used to calculate various indices that characterize the downstream impedance of the umbilical artery. The indices commonly calculated include the umbilical artery systolic-diastolic (S/D) ratio, resistance index (RI), and pulsatility index (PI). Following the evaluation, the physician reviews the ultrasound imaging, calculates the relevant indices, assesses the umbilical artery blood flow velocity, and generates a written report summarizing the findings. It is important to note that for fetal Doppler velocimetry of the middle cerebral artery, a different code, CPT® Code 76821, is utilized, which involves similar procedural steps but focuses on the middle cerebral artery instead.