Barts and The London Renal Centre | For patients | Frequently asked questions
Frequently asked questions
Kidney biopsies
Below are some common questions and answers about a kidney biopsy:
Q: What is a kidney biopsy?
A: A kidney biopsy involves taking a very small sample from the kidney (about 20 functioning kidney units – each kidney normally has approximately 1 million units) and examining it in minute detail.
Q: Will I need to come into hospital?
A: You will come as a day-case and will normally be admitted to the ward on the morning of the biopsy where a nurse or doctor will ensure that your medical condition has not changed since your last visit. Your blood pressure will be measured, urine checked and blood tests may be sent. Too high blood pressure could delay the biopsy. You should usually not have taken asprin or clopidogrel or pain killers containing asprin for one week before the biopsy. The precise timing of when you should stop taking any medication should be discussed with you prior to biopsy.
Q: How is a kidney biopsy performed?
A: The biopsy is performed by a doctor who uses an ultrasound scanner to view the kidney during the biopsy. You will be asked to lie on your tummy. The skin over your back just below your ribs is cleaned and some local anaesthetic is injected. This will sting a little at first. More local anaesthetic is then put into the muscle of the back.
When the skin and tissue are completely numb the doctor finds the kidney using the ultrasound and then will make a small cut in the skin and insert a fine needle into the kidney. You are usually asked to take a breath in and hold it for a few seconds while the biopsy is taken. This may be repeated a few times and you should not be aware of any pain but may feel a little pressure when the biopsy needle is used. The whole procedure usually takes approximately 40 minutes.
Q: What if a biopsy is taken from a transplant kidney?
A: If it is a biopsy taken from a transplant kidney you will be asked to lie on your back and the local anaesthetic will be put into the skin and then the muscles of your tummy over the transplanted kidney. The biopsy is then taken the same way.
Q: What happens after the biopsy?
A: Following the biopsy you will rest in bed for up to 6 hours – 2 hours lying flat and then 4 hours sitting up. Your blood pressure and pulse will be measured frequently at first, say every 15 minutes and then at regular intervals. The first urine you pass following the biopsy should be given to the nurse who will check to see if there is any bleeding. You will be able to eat and encouraged to drink plenty of fluids. You may have some pain or discomfort after the biopsy and you can take 1-2 paracetamol tablets every 6-12 hours for the first day.
Provided all is well with your blood pressure, pulse and urine, you can go home at the end of the day. It is best to arrange for someone to drive you home.
Q: When do I get the results?
A: It normally takes our laboratory 48 hours to compile a preliminary report. If the preliminary report indicates that we need to see you sooner, then we will organise this with you. Otherwise, a full report normally takes a week to complete. Your doctor will discuss the results of the biopsy with you at the clinic. The results will also be sent to your GP.
If the biopsy has been done urgently, then some results may be available within 24 hour.
Q: Are there any risks associated with a kidney biopsy?
A: Complications associated with a kidney biopsy are rare. One of the risks is bleeding and you will be monitored carefully following your test to detect this (changes in pulse rate, blood pressure and blood in the urine are all checked).
If there are any signs of bleeding, you may need to go back to the radiology department for an ultrasound scan to check why there is bleeding. The majority of bleeding is minor and requires no special treatment.
An unexpected amount of bleeding is rare and may call for a blood transfusion or special x-ray called an angiogram which will help find the bleeding point and sometimes stop the bleeding. However, this is very rare and reported in less than 1% of biopsies.
If you are worried or unwell at home after a kidney biopsy. Telephone the Paulin Ward:020 7377 7644 or contact The Royal London Hospital switchboard on 020 7377 7000 and ask for the renal doctor on call.
Vascular access
Below are some questions and answers which explain the importance of surgical vascular access:
Q: Why is vascular access required?
A: Your blood will need to be removed, cleaned and returned during your dialysis session, this replaces the role of your kidneys. To allow for this to happen there needs to be a point on your body where your blood supply can be easily accessed.
Q: When should I have vascular access surgery?
A: A vascular access should be prepared a few months before your start dialysis. This will allow for easier and more efficient removal, cleaning and replacement of your blood, and you should hopefully have fewer complications than would be experienced with temporary access.
Q: Are there different types of vascular access?
A: Yes. There are three basic types of vascular access for haemodialysis: an arteriovenous (AV) fistula, an AV graft and venous catheter.
Arteriovenous (AV) fistula
A surgeon creates an AV fistula by connecting an artery directly to a vein, usually in the forearm. In most cases, the procedure can be performed on a day-case basis. Some patients may stay in hospital one night following the procedure. A fistula should provide good blood flow for dialysis and should last the longest time of all access types. To find out more go to www.fistulafirst.org/patients/patients.php
Arteriovenous graft
If a patient has small veins that will not develop into a fistula, then vascular access that uses a synthetic tube can be implanted under the skin the patient’s arm. The tube becomes an artificial vein that can be used repeatedly for needle placement and blood access during haemodialysis.
Venous catheter (temporary access)
A temporary haemodialysis line may be referred to as a catheter. These lines have two openings - one is red (arterial) an opening to take blood out of your body into the dialysis machine and the other is blue (venous) an opening that allows the cleaned blood to be returned to your body.
Q: Is there anything I should do to take care of my vascular access line?
A: By taking good care of your vascular access line, it will last longer and should help you prevent problems such as infecting and clotting. Here are some important steps to take:
- Keep the line dressing clean and dry
- Make sure the area of the insertion site is clean anddry
- Never unscrew the cap at the end of your line
- It is best not to shower or swim. Take baths but keep the line and dressing dry
- The caps and the clamps of your line should be kept tightly closed when not being used for dialysis
- If the area around your line feels sore or looks red it is best to contact one of the nurses at your haemodialysis unit.
Q: How should I care for my line dressing?
A: A special dressing will be applied over where the line goes into your skin. The dressing is put on in a specific way by one of the nurses in the dialysis unit, for this reason it is best not to change your dressing at home. If your line dressing does fall off at home you will need to replace this one with a new one. To do this is it important to follow these steps:
- Wash your hands thoroughly with hot soapy water for at least 3 minutes and dry your hands using a clean towel
- Open the wrapper and remove the dressing, making sure you do not put the clean dressing down onto a surface
- Be careful not to touch the sticky side of the dressing, then remove the plastic pieces with the green writing
- Place the centre pad of the dressing over where the line goes into the skin
- Press down lightly around the edges of the dressing to stick it down
If your line comes out call 999 and explain what has happened.
