What does the kidney do and how does it work?

The kidney filters the fluid part of the blood and produces urine. It does this by forcing the blood through a vast number of tiny knots of capillaries known as glomeruli. These are located in the kidney cortex.
From the inside out, these capillaries are made up of capillary lining cells, a layer of a protein feltwork (known as the glomerular basement membrane) and on the outside a covering of another cell type.
The dissolved molecules and water, which the body needs, are then returned to the blood stream, leaving the remainder as urine, which travels to the bladder via the ureter.

What is a renal biopsy?

A renal biopsy is a tiny piece of kidney, which is removed from a patient and sent to a hospital laboratory in order to find out why the kidney isn’t working properly.

When is it necessary to have a renal biopsy done?

If the urine consistently has a lot of protein or blood in it, and the consultant renal physician isn’t sure precisely why.

Blood tests will also tell if the kidney isn’t working properly.

How is a renal biopsy done?

Firstly, using an ultrasound scanner the kidney is located. Then, using a long needle-like instrument, a piece of tissue approximately 12 millimetres by 1 millimetre is painlessly removed.

Is one piece of tissue enough to make a diagnosis and to tell whether long-term dialysis is likely to be needed?

Often, but unfortunately, not always. Kidney biopsies need to be looked at using three different microscopes: a light microscope, a fluorescence microscope, and an electron microscope. For technical reasons, the ways the three techniques work sometimes make it necessary to process them differently, with the requirement for up to three biopsies to be taken.