Dialysis is where a machine used to replace a kidney after kidney failure. The word dialysis comes from the Greek Word dialysis, dia meaning –through and lysis meaning – loosening.

Dialysis can be used for people who have become sick and have lost the use of their kidneys for a short time, or for people who no longer have working kidneys. The purpose of the kidney is to keep a balance of water and minerals in the body. These minerals include sodium, potassium, chloride, calcium, phosphorous, magnesium and sulphate. The kidneys also take out hydrogen ions from the blood. Dialysis is able to remove these wastes from the body and helps to keep the minerals in balance.

However, the kidneys are also part of the endocrine system and make erythropoietin and calcitriol.


Dialysis machines work by using diffusion and ultrafiltration. A very fine material, called a membrane, allows blood and fluid to flow through it. In the machine, the blood flows in one direction and on the other side of the membrane, a special fluid, dialysate flows in the opposite direction, this process is known as OSMOSIS.  Dialysate is a fluid that has different chemicals in it. A doctor would decide what mixture of chemicals would be needed for each patient. The dialysate has bicarbonate in it to lower the higher acid levels that these patients often have. The blood and dialysate mix together. The waste products are removed from the blood and caught up in the fine membrane.