Before<unk>  Like most invasive medical procedures, a<unk>  is not without risk (see Complications). A nephrologist will have to satisfy themselves that a<unk>  is of appropriate benefit to justify the risks of the procedure before proceeding. This will include careful consideration of patient characteristics and other clinical information obtained from history, examination and other less-invasive investigations. Blood testing may be done before the<unk>  to ensure that there is no evidence of infection or a blood clotting abnormality. Further, an ultrasound or other imaging study of the kidney may be performed before<unk>  to exclude structural problems of the kidney, which may theoretically increase the risk of the procedure. These include hydronephrosis, pre-existing arteriovenous fistula in the kidney, cystic kidney disease and small, shrunken kidneys. To decrease the risk of bleeding, patients are usually advised to avoid medicines that impair clotting for one to two weeks before the<unk> . These medications include aspirin, clopidogrel, heparin and warfarin. Desmopressin may be administered intravenously in the hope of reversing the clotting disturbance that accompanies kidney failure (uraemic coagulopathy). Strict control of blood pressure is also sought to reduce bleeding risk. Prior to the procedure, informed consent is usually taken. Arrangements will also be made to ensure that appropriate post-biopsy care and supervision is in place. Fasting is usually not required. However, this will depend on centre preference. During<unk> <unk>  is typically performed by a nephrologist or interventional radiologist. The<unk>  is planned with the assistance of ultrasound or CT scanning to visualise the location and depth of the kidneys immediately before the<unk> . In the case of a native kidney<unk> , the procedure will be performed with the patient lying on their stomach (prone) or on their side (lateral decubitus position). For transplant<unk> , the patient lies on their back (supine). The<unk>  procedure usually takes about 15 minutes. The site of<unk>  is prepared antiseptic solution and sterile drapes are applied. If<unk> -time imaging is used, sterile coverings will be placed on the equipment. The person performing the procedure (proceduralist) will wash their hands and don a sterile gown and gloves. A mask may or may not be worn. The<unk>  is usually performed while the patient is awake or with mild sedation. Use of a general anaesthetic is typically not required. After the site is prepared, the proceduralist injects local anaesthetic into the skin, through the subcutaneous tissue and down to and around the kidney. There may be a sharp sting as the local anaesthetic is injected. After a few seconds, the site will be numb and only a sensation of pressure should be felt. A small 1–2 mm incision is made to allow insertion of the<unk>  needle. In most cases,<unk> -time imaging will be used to guide positioning of the local anaesthetic and<unk>  needles. In the case of blind<unk> , this will not be used. A loud click may be heard as the spring-loaded<unk>  needle is fired into the kidney to obtain a tissue sample. The resulting core of kidney tissue is usually less than 1 mm in diameter and up to 1 cm long. This may be done more than once to obtain sufficient kidney tissue. A pathologist or pathology scientist may be present at the<unk>  to examine the core(s) of kidney tissue for adequacy under a low power microscope. They will inform the person performing the procedure about how much kidney tissue was obtained, specifically how of<unk>  sample is kidney cortex and how much is kidney medulla. In some centres, this role will be performed by the proceduralist with the naked eye. When enough kidney tissue has been obtained, pressure will be applied to the<unk>  site. After a period of time, it will be cleaned and dressed. Sutures are usually not required. After<unk>  Post-biopsy care will differ from centre to centre. Most hospitals will observe patients who have had<unk>  for 4–6 hours to minimise the risk of bleeding. Blood pressure and urine are frequently monitored to ensure the patient is not suffering any bleeding complications. Mild-moderate pain is managed with simple analgesics such as paracetamol or acetaminophen. Severe pain is usually an indication of bleeding complication, and may prompt a longer hospital stay and further tests. If there are no observed complications during this period, most hospitals will discharge patients and allow them to return home. Other centres will admit patients who have had<unk>  overnight for observation. Most hospitals will discharge patients post-renal<unk>  with written instructions on what to do if complications occur.
Renal biopsy
Renal ultrasonography
Radioisotope renography
Ureteroscopy
Urine protein/creatinine ratio
Urine cytology
BUN-to-creatinine ratio
Microalbuminuria