Novel assembly

Claim 1

An assembly for the collection, separation and isolation of serum or plasma from blood, which comprises; a. a tubular container having an open end and a closed end and which together with its ends defines a blood collection chamber; b. a self-sealing, cannula-penetrable, elastomeric closure member hermetically sealing said open end; c. a thixotrope reservoir secured to an inner wall of said container adjacent to said closure member, which comprises; i. a tubular body having a closed lower end which defines a thixotrope holding space, ii. a conduit passing through the center of said reservoir and providing communication between the adjacent closure member and said blood collection chamber; and iii. an open nozzle extending downwardly from said reservoir along an inner wall of said container and providing communication between said holding space and the blood collection chamber, said nozzle being of a dimension which is insufficient to permit the passage of a thixotrope under the force of one gravity but sufficient to permit the passage of said thixotrope under centrifugal force; and d. a thixotropic sealant disposed in said holding space, said thixotrope being inert with respect to the blood and having a specific gravity within the range of from about 1.03 to about 1.09; said assembly being sufficiently air-evacuated to provide at least a partial vacuum in said blood collection chamber.