Evacuated sample collection tube with aqueous additive

摘要

The invention relates to an evacuated assembly for collection of a sample of a body fluid from a subject's body comprising: a hollow tube defining an existing axis having an open end and a closed end defining a chamber therein for receiving a sample of a collected fluid from a subject; a resilient closure disposed in said open end to close said chamber and to form a seal capable of maintaining a pressure differential between atmospheric pressure and a pressure less than atmospheric pressure within said chambers; an aliquot of an aqueous additive for treating the fluid sample; a matrix formed from a fibrous material having capillary spaces therein for absording said aliquot of said aqueous additive; an aliquot of water immiscible liquid having a specific gravity greater than about 1.07 for encapsulating said aqueous additive absorbed on said matrix; and a normally closed resilient valve disposed in said chamber to contain said aqueous additive, said liquid and sid matrix between said closed end and said valve, said valve being openable when the sample is in chmaber by centrifugation of said tube thereby to allow lower density fractions of the sample and said aqueous additive to collect above said valve and to mix.