Adrenal Vein Sampling 

Download and print as a PDF (207kB pdf)

What is this information about?

This information explains how to prepare for and recover from an adrenal vein sampling (AVS) procedure. It includes advice on: 

• What adrenal vein sampling is 

• How to prepare for the procedure 

• What happens on the day of the procedure 

• What to expect after the procedure 

• Possible risks 

• Where to find further help and advice 

Why have I been given this information?

You have been given this information because your doctor has diagnosed you with high aldosterone levels, which can cause high blood pressure.  

To find out whether one or both of your adrenal glands are producing too much aldosterone, your consultant has referred you for an adrenal vein sampling test.  

Following the advice in this leaflet will help ensure the procedure goes smoothly and safely. 

What is adrenal vein sampling?

Adrenal vein sampling (AVS) is a test that helps doctors determine if one or both adrenal glands are making too much of the hormone aldosterone.  

This test can provide important information that scans might not show. It helps doctors: 

• Find out why your blood pressure might be high 

• Decide if you might need surgery 

• Locate glands that may not be visible on scans 

• Check if a gland is affected by disease 

Must I follow any special instructions before the procedure?

Yes, to make sure the test is accurate and safe, you need to follow these instructions: 

• Medications: 
  • If you take blood-thinning medications (for example, aspirin, clopidogrel, warfarin), call the hospital as soon as you get your appointment letter. You may need to stop taking these for a short time before the test. 
  • If you take diabetes medication (for example, metformin or insulin), you may need to adjust your dose. Contact the hospital for advice. 
  • Some blood pressure medications can affect your test results. If your doctor has not told you which ones to stop, call the hospital to check. 

• Salt intake: You should not reduce your salt intake before the test. Eating enough salt is important. 

• Blood test: You need to have a blood test to check your potassium levels 2–3 days before the test. This will be requested by your referring doctor. 

• Allergies: If you have had an allergic reaction to the dye used in CT scans before, tell your doctor. 

Where will the procedure take place?

The test will be done in a special X-ray room by a specialist doctor called an Interventional Radiologist. 

What happens on the day of the procedure?

What are the steps of the procedure?

• You will lie on your back while sterile sheets cover you. 

• About 30 minutes before the test, a nurse will give you an injection in your arm to stimulate your adrenal glands. 

• A doctor will numb your groin with a local anaesthetic and insert a thin tube (catheter) into a vein. 

• They will inject a special dye to check that the tube is in the right place. 

• The doctor will take blood samples from both adrenal veins and a central vein. Adrenal veins drain blood from the adrenal glands which are on top of each kidney, the central vein carries blood back to the heart from the other parts of the body. 

• Once the samples are collected, they will remove the tube and press gently on the area to prevent bleeding. 

• The procedure usually takes about one hour, but it may take longer if the veins are difficult to reach. 

• In rare cases, the test may need to be repeated. 

What should I do after the procedure?

You will need to stay in the hospital for two hours after the procedure to be monitored. 

Will I be able to drive after the procedure?

• Do not drive for two days to avoid problems with your groin. 

• Ask a friend or a family member to take you home, as you may feel weak or sleepy. 

How should I take care of my wound?

Check the area in your groin for bleeding or swelling. If bleeding occurs, lie down, press firmly on the area, and call the hospital. 

When will I get my results?

Your doctor will discuss the results with you at your follow-up appointment. 

What are the possible risks?

• Minor risks include bruising, bleeding, or infection. 

• There is a very small risk (less than 1%) of an allergic reaction to the injection given before the test. 

• Serious complications, such as damage to the adrenal veins, are very rare. 

Where can I find further information or advice if I need it after I have read this information?