Abstract: A readily penetrable vacuum indicator closure for sealing an open end of an air evacuated blood collection tube. The closure comprises a flexible tubular body with an open first end and a closed second end formed by a penetrable, flexible end wall, with the end wall having an inner surface and an outer surface. When pressure on the inner and outer surfaces is substantially equal, the outer surface is convexly curved and the inner surface is concavely curved. This end wall is sufficiently flexible to deflect under the influence of a pressure differential on the end wall, such as may be perceived when the closure seals an evacuated blood collection tube. The outer surface of the flexible end wall is readily visible, thus serving as an indicator of relative pressures on opposite sides thereof. A flange is annularly disposed about the periphery of the tubular body adjacent to the second end.

Abstract: A self-contained fluid separator assembly is disclosed capable of separating blood into its component parts of plasma or serum, the light phase, and the cellular portion, the heavy phase. The assembly comprises a container having at least one open end for receiving blood for subsequent separation and a closure sealing the open end of the container. The closure is formed of a self-sealing elastomeric material which is penetrable by a pointed hollow needle through which the blood to be separated is conducted into the container. A piston is slidably disposed in the container with its outer surfaces in sealing contact with the inner surfaces of the container. Centrifugally actuated valve means is provided on the piston which is normally closed and automatically opens in response to centrifugal force. When blood in the container is subjected to centrifugal force it first separates into its light phase and heavy phase.