Serum preparator

Claim 1

A serum preparator for enabling the separation of serum from blood, for filtering particulates from separated serum, and for partitioning serum filtrate from unfiltered blood, the blood contained within a tube adapted for centrifugation, the cellular components of blood sedimenting within the tube during centrifugation, thereby forming a cellular pellet and a supernatant of serum, the serum preparator comprising: a piston adapted to be inserted into the open end of the tube and to sediment within the bore of the tube during centrifugation, and defining an aperture for the passage of serum through the piston during sedimentation, an annular seal between the piston and the tube for preventing blow-by of serum around the piston during sedimentation of the piston, thereby forcing displaced serum to pass through the aperture, a filter covering the aperture for filtering particulates from serum passing through the aperture, the filter sealed to the piston for preventing serum blow-by around the filter, and means for restraining the sedimentation of the piston during centifugation, the restraining means attached to the piston and contacting the tube for support, said restraining means holding and positioning the serum preparator at a catch position after insertion into the tube, said restraining means adapted to restrain the sedimentation of the serum preparator during centrifugation to enable the cellular components of blood to sediment sooner to the cellular pellet than the serum preparator, said restraining means including a detent attached to the piston and contacting the tube for positioning and holding the piston above the serum in the tube above the blood and for releasing the piston for travel down the bore of the tube, the release induced by the application a triggering force which forces the detent from its support position, the sedimentation of the piston within the tube causing passage of displaced serum through the aperture and across the filter, thereby filtering the serum, said serum preparator having a density approximately isopycnic with the density of blood, greater than the density of serum, and less than the density of the cellular pellet, thereby causing the serum preparator to have a stop position at isopycnic sedimentation equilibrium partially submersed in the cellular pellet and partially overlayed by the serum, said piston, annular seal, and filter acting in combination at the stop position to obstruct the passage of particulates across the serum preparator thereby partitioning the serum filtrate and the cellular pellet for preventing contamination of the serum filtate during storage and decanting.

Claim 16

A method for separating serum from blood, for filtering the separated serum, and for partitioning the serum filtrate from unfiltered blood, the method using a tube for containing the blood and a serum preparator for filtering and partitioning the blood, the serum preparator having a density approximately isopycnic with blood and having, a piston adapted to insert into the tube and to sediment within the tube and defining an aperture for the passage of serum, an annular seal betweem the piston and the tube for preventing blow-by of serum around the piston during sedimentation and for forcing displaced serum to pass through the aperture, a filter covering the aperture for filtering particulates from serum passing through the aperture, the filter sealed to the piston for preventing serum blow-by around the filter, and a means for restraining the sedimentation of the piston, the restraining means attached to the piston, and including a detent attached to the piston and contacting the tube for positioning and holding the piston above the serum in the tube above the blood and for releasing the piston for travel down the bore of the tube, the piston, annular seal, and filter acting in combination to obstruct the passage of particulates across the serum preparator, the method comprising steps for, inserting the serum preparator into the tube containing the blood, for loading the assembled tube and serum preparator into a centrifuge rotor, for first spinning the loaded assembly in the rotor at a first speed sufficient to separate the serum and cellular components of blood and less than sufficient to overpower the restraining means so as to restrain the sedimentation of the serum preparator and to enable the cellular components of blood to sediment sooner to the cellular pellet than the serum preparator, and for second spinning the loaded assembly in the rotor at a second speed sufficient to overcome the restraining means so as to enable the serum preparator to sediment within the tube and to cause displaced serum to pass through the aperture and across the filter, thereby filtering the separated serum, said second spinning continued until the serum preparator has reached a stop position and established a partition thereat, said inserting of the serum preparator into the tube establishing a contact between the restraining means and the tube, thereby causing the serum preparator to be held at a catch position within the tube, said second spinning continuing until the sedimentation of the serum preparator effectively reaches the stop position at isopycnic equilibrium near the interface between the separated serum and the cellular pellet and establishes a partition thereat for preventing contamination of the serum filtrate by the cellular pellet during storage and decanting.

Claim 17

A method for separating serum from blood, for filtering the separated serum, and for partitioning the serum filtrate from unfiltered blood, the method using a tube for containing the blood and a serum preparator for filtering and partitioning the blood, the serum preparator having a density approximately isopycnic with blood and having, a piston adapted to insert into the tube and to sediment within the tube and defining an aperture for the passage of serum, an annular seal betweem the piston and the tube for preventing blow-by of serum around the piston during sedimentation and for forcing displaced serum to pass through the aperture, a filter covering the aperture for filtering particulates from serum passing through the aperture, the filter sealed to the piston for preventing serum blow-by around the filter, and a means for restraining the sedimentation of the piston, the restraining means attached to the piston, and including a detent attached to the piston and contacting the tube for positioning and holding the piston above the serum in the tube above the blood and for releasing the piston for travel down the bore of the tube, the piston, annular seal, and filter acting in combination to obstruct the passage of particulates across the serum preparator, the method comprising steps for, inserting the serum preparator into the tube containing the blood, for loading the assembled tube and serum preparator into a centrifuge rotor, for first spinning the loaded assembly in the rotor at a first speed sufficient to separate the serum and cellular components of blood and less than sufficient to overpower the restraining means so as to restrain the sedimentation of the serum preparator and to enable the cellular components of blood to sediment sooner to the cellular pellet than the serum preparator, and for second spinning the loaded assembly in the rotor at a second speed sufficient to overcome the restraining means so as to enable the serum preparator to sediment within the tube and to cause displaced serum to pass through the aperture and across the filter, thereby filtering the separated serum, said second spinning continued until the serum preparator has reached a stop position and established a partition thereat, said inserting of the serum preparator into the tube establishing a contact between the restraining means and the tube, thereby causing the serum preparator to be held at a catch position within the tube, said second spinning continuing until the sedimentation of the serum preparator effectively reaches the stop position at isopycnic equilibrium near the interface between the separated serum and the cellular pellet and establishes a partition thereat for preventing contamination of the serum filtrate by the cellular pellet during storage and decanting.