Answer
The dialysate should be free of waste products and should have an electrolyte concentration that will balance the electrolytes in the patients blood back to normal levels
Work Step by Step
There are standard dialysate concentrations, which have a somewhat higher concentration of ions like sodium and calcium than blood, but concentrations customized to match the needs of the patient are becoming more common.
Since the goal of dialysis is to create the correct electrolyte balance and remove waste products, the dialysate must have low concentration of what needs to be removed and higher concentration of what needs to be added to the blood.
