Fluid collection apparatus

Claim 1

A fluid collection apparatus for the separation of a mixture comprising: an elongate, transparent, hollow body having a first and a second open end; closure means for said first end of said body; a self-sealing septum sealingly disposed within said body adjacent the second end, said septum including a centrally disposed cavity extending axially from one end thereof and terminating in a normally closed slitted web portion at the opposite end thereof, and at least a pair of spaced apart inwardly extending ribs in said cavity; and a composite piston adapted to be inserted into the second end of said hollow body, said composite piston including a unitary body having a central passageway therethrough, hollow piercing means adapted to pierce said slitted web portion of said septum and provide communication between said central passageway and the interior of said hollow body, a filter element disposed within said central passageway, and a laterally extending flange extending beyond the outer wall of said hollow body whereby when said apparatus is inserted into a sample containing tube, said piercing means is caused to pierce said slitted web portion of said septum to allow a filtrate to pass through said filter element through said hollow piercing means and into the interior of said hollow body, such that when said apparatus is withdrawn from the sample containing tube said flange maintains said composite piston in the sample containing tube, and allows said web to seal when said piercing means is removed therefrom.