Method for filtering blood plasma flowing through bone marrow of a subject, including: providing an active filtering device having a pressure increasing mechanism and a filter material configured for filtering flowing blood plasma； attaching the active filtering device to bone inside the subject, the bone includes marrow through which flows blood plasma； exposing filter material to flowing blood plasma； applying pressure increasing mechanism so as to create pressure gradient between flowing blood plasma and filter material； filtering flowing blood plasma； and removing excess fluid from flowing blood plasma. During filtration, water and solutes of blood plasma move and pass through filter material, and waste substances of blood plasma are captured and retained by filter material, forming filtered flowing blood plasma. The active filtering device includes or is connectable to hemodialysis or/and ultrafiltration equipment through which filtered flowing blood plasma drains and is returned to the subject's bloodstream.
