Abstract: A blood specimen processor by means of which blood specimens are collected into a collection tube containing an anticoagulant and a molded buoy of predetermined density between 1.045 and 1.084 with an embedded water swellable o-ring that expands to form a robust seal in a leucocyte density gradient between the buoy's outer surface and tube's inner surface. The buoy is made of a first resin and a second resin, the first resin having a lower density than the second resin, the first resin and the second resin being present in such amounts and relative proportions so that the body has an overall density between 1.045 and 1.084 and preferably, a center of gravity below a geometric center of the body. When the blood specimen contained in the processor is centrifuged, the buoy is thrust through the separating blood and the developing interface of erythrocytes, leucocytes, and plasma.

Abstract: A blood specimen processor by means of which blood specimens are collected into a collection tube containing an anticoagulant and a molded buoy of predetermined density between 1.045 and 1.084 with an embedded water swellable o-ring that expands to form a robust seal in a leucocyte density gradient between the buoy's outer surface and tube's inner surface. The buoy is made of a first resin and a second resin, the first resin having a lower density than the second resin, the first resin and the second resin being present in such amounts and relative proportions so that the body has an overall density between 1.045 and 1.084 and preferably, a center of gravity below a geometric center of the body. When the blood specimen contained in the processor is centrifuged, the buoy is thrust through the separating blood and the developing interface of erythrocytes, leucocytes, and plasma.

Abstract: A separator has a generally cylindrical body and a water swellable material fitted around at least a portion of the generally cylindrical body or on the surface of a passage through the body. Upon being exposed to water the water swellable material swells to form a seal in the passage or within the tube or other vessel containing the separator. The separator is preferably used in a blood collection tube and has a specific gravity between specific gravities of a light phase and a heavy phase of the blood. After the blood has been collected and centrifuged the separator moves to a position between the light phase and the heavy phase and the water swellable material is exposed to water in the blood causing the material to swell and create a seal. Thereafter, the serum or plasma as well as white blood cells, lymphocytes, monocytes and platelets can be removed from the blood collection tube.

Abstract: A separator float has a generally cylindrical body and a water swellable band having a selected outer diameter fitted circumferentially around a portion of the generally cylindrical body. The water swellable band is made of a water swellable material so that upon being exposed to water the water swellable band swells to a greater outside diameter. The separator float is preferably used in a blood collection tube and has a specific gravity between specific gravities of a light phase and a heavy phase of the blood. After the blood has been collected and centrifuged the separator float moves to a position between the light phase and the heavy phase and the water swellable band is exposed to water in the blood causing the band to swell and create a seal. Thereafter, the serum or plasma as well as white blood cells, lymphocytes, monocytes and platelets can be removed from the blood collection tube.

Abstract: An automatic filling micropipette is formed from a tubular body having an open end, and being closed or having a piston at an opposite end. The tubular body is sized to permit liquid to flow into the tubular body by capillary action. An aperture is provided in the sidewall, the aperture having a diameter smaller than the diameter of the open end.

Abstract: A tube for collection, separation and dispensation of a two-phase fluid is provided with a elongated rigid tubular container having a fluid entry end a closable end and a float. The float retained within the tubular container is positioned between the light phase and the heavy phase of the fluid on centrifugation thereby separating the two phases. In dispensing the light phase, the float moves to and engages the fluid entry end thereby preventing the heavy phase from escaping out of the tube.

Abstract: A self-sealing fluid collection tube is provided with an elongated bore and a fluid entry end. A plug of super-absorbent material is provided within the tube opposite the fluid entry end. This plug is preferably vented and is adapted to seal the tube by expanding when contacted by a fluid, such as blood. After the fluid has been collected, the tube is placed in a pipetter-dispenser in which a plunger, which is inserted into the tube, moves through a calibrated distance thereby advancing the plug into the tube and expelling a selected volume of fluid from the tube. Alternatively, the fluid may be transferred into another receptacle by piercing the sealed plug to form a new vent channel to permit drainage of the collected fluid into a receptacle.

Abstract: An automatic filling capillary pipet having a tubular body defining an elongated bore having a fluid entry end. The interior surface of the tubular body having a first zone with hydrophobic means for resisting wetting by aqueous liquids. The tubular body interior surface having a second zone which is hydrophilic with respect to aqueous fluids. Introduction of an aqueous fluid into the elongated bore will effect retention therein of a predetermined volume of aqueous fluid proportional to the cross section of the bore and the length of the second zone. In one embodiment the hydrophobic first zone originates at a position spaced from the fluid entry end and the hydrophilic second zone is disposed between the first zone and the fluid entry end. In another embodiment a hydrophobic third zone is disposed intermediate the hydrophilic second zone and the fluid entry end.