A Doppler test is a non-invasive medical test that uses sound waves to show blood moving through blood vessels. It is named after Christian Doppler, a 19th-century physicist who discovered a way to measure sound waves reflected from moving objects. The test can be used to estimate the blood flow through blood vessels by bouncing high-frequency sound waves. There are different types of Doppler ultrasound tests, including:

• Color Doppler: This type of Doppler uses a computer to change sound waves into different colors. These colors show the speed and direction of blood flow in real-time.

• Spectral Doppler: This test shows the graphical representation of blood flow over time.

• Duplex Doppler: This test combines traditional ultrasound pictures with Doppler ultrasound. It can check the width of blood vessels and can help show blockages.

Doppler ultrasound tests are used to help healthcare providers find out if a person has a condition that is reducing or blocking their blood flow. It may also be used to help diagnose certain heart diseases. The test is most often used to:

• Check heart function. It is often done along with an electrocardiogram, a test that measures electrical signals in the heart.

• Look for blockages in blood flow. Blocked blood flow in the legs can cause a condition called deep vein thrombosis (DVT) .

A Doppler test is a safe, painless way for healthcare providers to assess the health of blood vessels and check for cardiovascular problems. The test may take 30 to 60 minutes, and the results are available right away for the doctor to review.