1. Method of dialysis in which blood from a patient’s body is circulated through an external device or machine and then returned to the patient’s bloodstream. Such an artificial kidney machine is usually designed to remove fluids and metabolic end products from the bloodstream by placing the blood in contact with a semipermeable membrane, which is bathed on one side by an appropriate chemical solution, referred to as dialysate . 2. Treatment usually done in a dialysis facility but can be done at home with the proper training and supplies. HD uses a special filter called a dialyzer or artificial kidney to clean the blood. The filter connects to a machine. During treatment, the blood flows through tubes into the filter to clean out wastes and extra fluids. Then the newly cleaned blood flows through another set of tubes and back into the body.