Serum separation device

DETAILED DESCRIPTION OF THE INVENTION FIGS.
1, 3, and 4 represent a common embodiment of the invention.
Tubular element 3, being the inner of the two tubular structures is fitted at one end with stopper 2.
Said stopper being provided with air vent 12 is used to provide means of sealing the system from the outside enviornment and a means to allow blood to enter the system by needle penetration.
A filter device 4 constructed in a tubular fashion is permanently placed at one end of tube 3 at base 7 whereby plural openings 5 are provided immediately adjacent to said filter to allow serum to pass through and be stored in spaces within the outer tube 1.
The filter device 4 is of such porosity that serum is allowed to pass through while holding back clot and cellular material.
Since blood cells range in size from approxamately 7-12 microns a filter pore size substantially less than 7 microns must be used.
Such filters are manufactured by Gelman, and spectrum Medical Industries and are of the polycarbonate and cellulosic membrane types.
FIG.
3 illustrates the invention as it would normally appear prior to venapuncture.
Tubular element 3 is shown as being contained in outer tubular element 1.
Vent hole 12 is used to allow air to escape during the evacuation process, and this vent is sealed off by the wall of the outer tube when the stopper is pressed or forced in place after evacuation.
At the bottom of element 3 is a solid circular base 7 which is an integral part of said tubular element 3.
This base supports the filter at the bottom so that the force of centrifugation does not tear or rupture the filter membrane.
This base 7 is provided with plural openings 5 which allow serum to pass from the filter into spaces 6 below element 3, and spaces within tubular element 1.
In this respect it is pointed out that tubular element 3 must fit tube 1 in such a manner that adequate or substantial space is provided for serum to be stored inbetween the outer walls of tube 3 and inner walls of tube 1.
FIG.
4 illustrates the invention as it would appear after centrifugation