Hemofiltration is a medical procedure that involves removing excess fluid, waste products, and toxins from the blood. Synonyms for hemofiltration include renal replacement therapy, blood filtration, ultrafiltration, plasma exchange, and blood purging. Renal replacement therapy refers to the use of hemofiltration to treat kidney failure. The term ultrafiltration is used to describe a more focused form of hemofiltration that specifically removes excess fluid from the blood. Plasma exchange is a special type of hemofiltration that involves removing the patient's plasma and replacing it with donor plasma. Blood purging, on the other hand, is a term that describes the process of removing harmful substances from the blood using special filters.