While healthy kidneys have several functions in the body, the most well-known job is to produce urine. When kidney function goes below 10% to 15% kidneys are no longer able to filter the blood and make urine. This causes toxins to build up in the body along with excess fluid. Fortunately, we live in a time when there are treatments and medicines that can replace the functions of the kidneys and keep the body alive. One type of renal replacement therapy — meaning a treatment that replaces kidney function — is hemodialysis. Hemodialysis is a therapy that filters waste, removes extra fluid and balances electrolytes (sodium, potassium, bicarbonate, chloride, calcium, magnesium and phosphate).