If the kidneys become diseased and stop working, it is necessary to use a kidney machine to remove waste products from the blood. This machine process is called dialysis. It involves pumping blood from a tube in the person’s arm into thin tubing that runs through a tank of sterile liquid. Waste passes through the blood through the walls of the tubing, and the cleaned blood is returned to the body. The dialysis machine works the same way as the two main blood vessels running to and from the kidneys. One tube takes the unfiltered blood from the body (like the renal artery), while another tube takes the cleaned blood back into the body (like the renal vein). This process has to be done throughout the person’s life, unless a new kidney can be provided in a transplant operation. Dialysis needs to be carried out frequently, several times a week, to stop wastes from building up to a dangerous level.