A method and apparatus for separating serum from other blood components in a centrifuge tube. The separator comprises a cylindrical, laterally-expandable filter element composed of a multiplicity of generally longitudinally-oriented fibers, 10 to 40 millimicrons in diameter, formed of a biologically...http://www.google.fr/patents/US4369117?utm_source=gb-gplus-shareBrevet US4369117 - Serum separating method and apparatus
