There are two main types of concentrates for hemodialysis: acid and bicarbonate (base). Treated water is mixed with acid and bicarbonate concentrates to form the dialysis fluid (dialysate). Hemodialysate (dialysate) is the fluid and solutes that flows through the dialyzer during a hemodialysis process. After the combination of the bicarbonate concentrate, acid concentrate and water, the final dialysate can contain two or three buffer components, which depend on the acid concentrate used. The buffers are bicarbonate from the bicarbonate concentrate, citrate and/or acetate from the acid concentrate.