EP0098150A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Serum preparator
Assignee: ELITechGroup Inc
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Filing: 1983-06-28
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Granted: —
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Expires: 2003-06-28
Abstract
Abstract @ The invention is a device (1) and a method for preparing serum from blood. The invention is used in conjunction with the centrifugal separation of serum from blood for filtering fibrin and other particulates from the separated serum and for partitioning the serum filtrate from unfiltered blood; during the first phase of centrifugation, a detent (10) holds the serum preparator in check within the centripetal end of a tube (2) containing the blood while the components of blood separate by sedimentation and backflow. Once all cellular components have sedimented to the pellet, the second phase of centrifugation begins and the sedimentation of the serum preparator is initiated by a triggering centrifugal force. During sedimentation, the serum preparator forces displaced serum to pass across a filter (11) spanning an aperture (17) through the serum preparator. The sedimentation velocity of the device and the rate of filtration are controlled by a brake (6) on the serum preparator. The serum preparator is a density device which is approximately isopycnic with normal whole blood. The density of the serum preparator causes it to seek an isopycnic equilibrium stop position near the interface of the separated serous and cellular components. At the isopycnic stop position, the serum preparator forms an impermeable barrier to protect the serum filtrate from contaimination by the cellular component during storage and decanting.
Inventors
- 👤 John Raymond Wells
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 15:43
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/483; G01N33/487; G01N33/49; G01N33/491
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
397 words
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 being 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 (9) 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 (17) for the passage of serum through the piston (9) during sedimentation, an annular seal (18) for fitting between the piston (9) and the tube for preventing blow-by of serum around the piston (9) during sedimentation of the piston (9), thereby forcing displaced serum to pass through the aperture (17), and a filter (11) covering the aperture (17) for filtering particulates from serum passing through the aperture, the filter (11) being sealed to the piston (9) for preventing serum blow-by around the filter, the sedimentation of the piston (9) within the tube causing passage of displaced serum through the aperture (17) and across the filter (11), 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 (9), annular seal (18), and filter (11) 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 filtrate during storage and decanting, characterised in that the serum preparator further includes a means (10) for restraining the sedimentation of the piston during centrifugation, said restraining means being attached to the piston and capable of contacting the tube when the preparator has been inserted into the tube, said restraining means (10) being capable of holding and positioning the inserted serum preparator at a catch position within the tube, said restraining means (10) being 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.
Claim 2
Dependent Claim
397 words
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 being 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 (9) 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 (17) for the passage of serum through the piston (9) during sedimentation, an annular seal (18) for fitting between the piston (9) and the tube for preventing blow-by of serum around the piston (9) during sedimentation of the piston (9), thereby forcing displaced serum to pass through the aperture (17), and a filter (11) covering the aperture (17) for filtering particulates from serum passing through the aperture, the filter (11) being sealed to the piston (9) for preventing serum blow-by around the filter, the sedimentation of the piston (9) within the tube causing passage of displaced serum through the aperture (17) and across the filter (11), 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 (9), annular seal (18), and filter (11) 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 filtrate during storage and decanting, characterised in that the serum preparator further includes a means (10) for restraining the sedimentation of the piston during centrifugation, said restraining means being attached to the piston and capable of contacting the tube when the preparator has been inserted into the tube, said restraining means (10) being capable of holding and positioning the inserted serum preparator at a catch position within the tube, said restraining means (10) being 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.
Claim 3
Dependent Claim
78 words
A serum preparator as in claim 1, wherein the restraining means (10) includes a detent (10) attached to the piston and capable of contacting a support defined by the tube for positioning and holding the piston (9) above the serum in the tube above the blood and for releasing the piston (9) for travel down the bore of the tube when induced by the application of a triggering force which forces the detent (10) from its support position.
Claim 4
Dependent Claim
76 words
A serum preparator as in claim 1 wherein the restraining means (10) includes a detent (10) attached to the piston and capable of contacting a support defined by the tube for positioning and holding the piston (9) above the serum in the tube above the blood and for releasing the piston (9) for travel down the boreof the tube when induced by the application of a triggering force which forces the detent from its support position.
Claim 5
Dependent Claim
62 words
A serum preparator as in claim 3 wherein the detent (10) includes a resilient catch (13) and an arm connecting the catch to the piston (9), the catch for resting on the support, the triggering force causing the release by the catch bending and sliding off the support by the application of the triggering force, the triggering force being a centrifugal force.
Claim 6
Dependent Claim
74 words
S. A serum preparator as in claim 3 wherein the detent includes a catch (16) with a point of weakness and an arm connecting the catch (11) to the piston (9),the catch being capable of resting on the support, the triggering force causing the release by the catch (16) rotating about the point of weakness and sliding off the support by the application of the triggering force, the triggering force being a centrifugal force.
Claim 7
Dependent Claim
57 words
A serum preparator as in any one of claims 1 to S,further characterised in that the serum preparator further includes a barrier partition (7) impermeable to solutes and attached to and positioned by the- piston (9) for preventing diffusion of solutes between the cellular pellet and the serum filtrate across the serum preparator at the stop position.
Claim 8
Dependent Claim
63 words
A serum preparator as in claim 6, characterised in that the barrier partition (7) is held by the piston (9) over the filter (11) and has a check valve (22) providing for passage of serum across the barrier partition during sedimentation, and forming a seal with the piston for preventing diffusion of solutes around and across the barrier partition at the stop position.
Claim 9
Dependent Claim
70 words
A serum preparator as in claim 7 wherein the check valve (22) of the barrier partition is held sandwiched by the piston (9) in a transverse position above the filter, the check valve (22) being open when the serum preparator is sedimenting for allowing the serum to flow through the aperture, the check valve (22) being closed at the stop position for partitioning the serum filtrate from the cellular pellet.
Claim 10
Dependent Claim
40 words
A serum preparator as in any one of claims 1 to 8, wherein the restraining means (10) further includes means (6) for braking the sedimentation velocity of the serum preparator, the braking means (6) being attached to the piston (9).
Claim 11
Dependent Claim
62 words
A serum preparator as in claim 9, wherein the braking means (6) includes one or more brake pads (6) and one or more brake springs (19) connecting the brake pads (6) to the piston, the brake springs (19) pressing the brake pads (6) against the wall of the tube for creating frictional drag for slowing the sedimentation velocity of the serum preparator.
Claim 12
Dependent Claim
18 words
A serum preparator as in claim 9 or 10 wherein the braking means (6) includes a hydraulic brake.
Claim 13
Dependent Claim
37 words
A serum preparator as in claim 11 wherein the hydraulic brake includes a constriction of the aperture (17), for limiting the passage of displaced serum across the piston, thereby slowing the sedimentation velocity of the serum preparator.
Claim 14
Dependent Claim
56 words
A serum preparator as in any one of claims 1 to 12, wherein the centre of mass of the serum preparator is displaced from the centre of volume towards the centripetal end of the serum preparator, thereby decreasing the sensitivity of the sedimentation equilibrium point to changes in the density of blood serum and cellular pellet.
Claim 15
Independent Claim
439 words
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 iso- pynic with blood and having a piston (9) adapted to insert into the tube and to sediment within the tube and defining an aperture (17) for the passage of serum, an annular seal (18) for fitting between the piston (9) and the tube for preventing blow-by of serum around the piston during sedimentation and for forcing displaced serum to pass through the aperture (17), a filter (11) covering the aperture (17) for filtering particulates from serum passing through the aperture, the filter being sealed to the piston (9) for preventing serum blow-by around the filter, and a means (10) for restraining the sedimentation of the piston (9), the restraining means attached to the piston (9), the piston (9), annular seal (18) and the filter (11) acting in combination to obstruct the passage of particulates across the serum preparator, the method including 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 serous and cellular components of blood and less than sufficient to overpower the restraining means (10) 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 (10) so as to enable the serum preparator to sediment within the tube and to cause displaced serum to pass through the aperture (17) and across the filter (11), thereby filtering the separated serum, said second spinning being continued until the serum preparator has reached a stop position and established a partition thereat, the method being characterised in that said inserting of the serum preparator into the tube establishing a contact between the restraining means (10)and the tube and 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 16
Independent Claim
439 words
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 iso- pynic with blood and having a piston (9) adapted to insert into the tube and to sediment within the tube and defining an aperture (17) for the passage of serum, an annular seal (18) for fitting between the piston (9) and the tube for preventing blow-by of serum around the piston during sedimentation and for forcing displaced serum to pass through the aperture (17), a filter (11) covering the aperture (17) for filtering particulates from serum passing through the aperture, the filter being sealed to the piston (9) for preventing serum blow-by around the filter, and a means (10) for restraining the sedimentation of the piston (9), the restraining means attached to the piston (9), the piston (9), annular seal (18) and the filter (11) acting in combination to obstruct the passage of particulates across the serum preparator, the method including 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 serous and cellular components of blood and less than sufficient to overpower the restraining means (10) 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 (10) so as to enable the serum preparator to sediment within the tube and to cause displaced serum to pass through the aperture (17) and across the filter (11), thereby filtering the separated serum, said second spinning being continued until the serum preparator has reached a stop position and established a partition thereat, the method being characterised in that said inserting of the serum preparator into the tube establishing a contact between the restraining means (10)and the tube and 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
Dependent Claim
84 words
A method as in claim 14, wherein the second speed of the said second spinning is sufficient to overcome the contact between the tube and the restraining means (10) so as to enable the serum preparator to escape its catch position and to sediment within the tube, but the second speed is not so excessive as to cause the restraining means (10) to fail to restrain the velocity of the sedimentation of the serum preparator so as to allow filter overload and/or filter blow-by.
References Cited (Backward Citations)
No citation records indexed.
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