Abstract: A blood separation composition for use in blood collection tubes. The composition comprises, as a gel-like material that is the main ingredient or the composition, a copolymer of sebacic acid with 2,2-dimethyl-1,3-propanediol and 1,2-propanediol. The separation composition may further comprise a thixotropic agent blended with the copolymer. The copolymer renders the blood separation composition stable and less flowable during storage, allowing it to form a stable partition barrier in each collection tube when centrifuged. The blood cells above the barrier are prevented from remaining within the serum, without any amount of harmful oily substances being released from the separation composition.

Abstract: A blood separation composition for use in blood collection tubes. The composition comprises a fatty acid amide(s) blended with a gel-like material which is the main ingredient of said composition. The amide(s) render(s) stable and less flowable the blood separation composition during storage, allowing it to form a stable partition barrier in each collection tube when centrifuged, with the blood cells above the barrier being prevented from remaining within the serum. The blood separation composition containing the fatty acid amide(s) does not release any harmful oily substance.