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Renal Duplex

Also known as: Renal doppler ultrasound

Duration: About 60 to 90 minutes

A duplex is a noninvasive test that combines both the doppler and the ultrasound. It can be performed on either your arteries or veins.

Areas generally tested:
Peripheral Arteries (arms & legs) – Arterial Duplex 
Carotid Arteries (neck) – Carotid Duples 
Renal Arteries (kidneys) – Renal Duplex

In a renal duplex, two different probes/ transducers (one for the doppler and one for the ultrasound) are used to measure how well the blood is flowing in the renal arteries.


  • To check for any stenosis/narrowings in the renal artery or arteries in the back
  • To check for decreased blood flow – ex: renal artery disease
  • To check for blood clots
  • To check for any bulgings/aneurysms
  • In cases of high or uncontrolled blood pressure
  • To monitor the kidneys after a transplant

Preparing for the test: 

Download Pre Test Instructions

How it is performed: 

  • A technician applies a gel over your back. 
  • The ultrasound probe is held firmly against your skin and glided in multiple directions as it sends out sound waves to the renal arteries. Images are created when the probe picks up sound waves that bounce back from the renal arteries. 
  • Then the doppler probe is held firmly against your skin and sends out sound waves to the red blood cells in the renal arteries. The blood flow is heard and assessed for any stenosis/narrowings or blockages. 

After the test:

  • Your cardiologist will discuss the result with you.
  • You can continue with your daily routine.
  • Ask your cardiologist if you have any questions or concerns.

Hansen KL, Nielsen MB, Ewertsen C. Ultrasonography of the Kidney: A Pictorial Review. Diagnostics (Basel). 2015;6(1):2. Published 2015 Dec 23. doi:10.3390/diagnostics6010002
O’Neill WC. Renal relevant radiology: use of ultrasound in kidney disease and nephrology procedures. Clin J Am Soc Nephrol. 2014;9(2):373-381. doi:10.2215/CJN.03170313
Ahmed S, Bughio S, Hassan M, Lal S, Ali M. Role of Ultrasound in the Diagnosis of Chronic Kidney Disease and its Correlation with Serum Creatinine Level. Cureus. 2019;11(3):e4241. Published 2019 Mar 12. doi:10.7759/cureus.4241