**5.1 Review of dialysate generation**

Modern dialysate contains bicarbonate; it also contains variable amounts of calcium and magnesium. If such a solution were stored for any length of time, calcium and magnesium would combine with bicarbonate and precipitate out of solution. Dialysate must also be at physiologic pH which is, unfortunately, ideal for bacterial growth. In order to avoid these untoward consequences, bicarbonate is kept separate from calcium and magnesium in separate solutions or powders. The nomenclatures for these concentrates are "Acid" and "Bicarbonate". The Acid typically consists of sodium, chloride, potassium, magnesium, calcium, dextrose, acetate, and sometimes citrate. The Bicarbonate concentrate consists of sodium bicarbonate with some brands containing some additional sodium chloride. Creation of dialysate is requires mixing the Acid and Bicarbonate solutions in exact proportions. This is performed in 'real time' in the dialysis machine based on the pre-mixed concentrates of Acid and Bicarbonate and the software programmed for each concentrate.
