A biopsy is a diagnostic test that involves collecting small pieces of tissue, usually through a needle, for examination under a microscope. A kidney biopsy can help find a diagnosis and determine the best course of treatment.
Hematuria (blood in urine)
Proteinuria (excessive protein in urine)
Impaired kidney function (excessive waste products in blood)
A pathologist will look at the kidney tissue samples to check for unusual deposits, scarring, or infecting organisms that would explain the patient's condition.
The patient should avoid food and fluids for 8 hours before the test.
Shortly before the biopsy, blood and urine samples are performed to make sure the patient doesn't have a condition that would make doing a biopsy less desirable.
Kidney biopsies are usually done in a hospital. Light sedation or general anesthesia can be used. If sedated, the patient should be given a local anesthetic before the needle is inserted.
The patient is instructed to lie on his stomach to position the kidneys near the surface of the back. The doctor will mark the entry site, clean the area, and inject a local painkiller. For a percutaneous (through the skin) biopsy, the doctor will use a locating needle and x-ray or ultrasound equipment to find the right spot and then a collecting needle to gather the tissue. The patient will be asked to hold his breath as the doctor inserts the biopsy needle and collects the tissue, usually for about 30 seconds or a little longer for each pass. A small "popping" sensation may be felt as the needle enters the kidney. The doctor may need three or four passes to collect the needed samples.
The entire procedure usually takes about an hour, including time to locate the kidney, clean the biopsy site, inject the local painkiller, and obtain the tissue samples.
After the Test
The patient should lie on his back for 12 to 24 hours. During this time, the back will probably feel sore. It is best to keep the patient overnight in the hospital after the procedure. Hematuria may persist normally for up to 24 hours after the test. Monitor your blood pressure and pulse, take blood samples to measure the amount of red cells, and examine the urine passed. On rare occasions when bleeding does not stop on its own, it may be necessary to replace lost blood with a transfusion.
A rare complication is infection from the biopsy procedure.
Bloody urine more than 24 hours after the test
Inability to urinate
Worsening pain in the biopsy site
Faintness or dizziness
Getting the Results
After the biopsy, the doctor will inspect the tissue samples in the laboratory under one or more microscopes, perhaps using dyes to identify different substances that may be deposited in the tissue. It usually takes a few days to get the complete biopsy results.
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