Hemodialysis is a medical treatment that removes waste products, toxins, and excess fluid from the blood when the kidneys can no longer perform this function adequately, typically in cases of kidney failure. During the procedure, blood is drawn from the body through a vascular access point (such as a fistula, graft, or catheter) and passed through a machine containing a filter called a dialyzer, which acts as an artificial kidney. Inside the dialyzer, blood flows along one side of a semi-permeable membrane while a special fluid called dialysate flows on the other side, allowing waste and excess fluid to move out of the blood through diffusion and filtration before the cleaned blood is returned to the body. This treatment is usually performed three times a week for about three to four hours per session, either at a dialysis center or at home .