Abstract: An analytical rotor for separating plasma whole blood comprises a rotor body having a sample application port in an upper surface thereof. Blood introduced to the sample application port is metered into a metering chamber by capillary flow while the rotor remains stationary. Excess blood passes into an overflow chamber by capillary flow, either simultaneously with the metered flow or after opening of a vent in the overflow chamber. Subsequent rotation of the rotor causes metered blood in the metering chamber to flow into a receiving chamber, typically a plasma separation chamber.

Abstract: A centrifugal rotor comprising a plurality of peripheral cuvettes and a collection chamber spaced radially inward from the cuvettes is disclosed. The rotor includes a means for introducing fluid into the collection chamber and plurality of generally radial inlet channels connecting each cuvette to the chamber. Each inlet channel has a discrete flow path for fluid to enter the cuvette and another discrete flow path for gas to exit the cuvette as the cuvette is filled. Positioned radially inward from each cuvette is a reflective surface capable of deflecting a light beam from a generally vertical direction to a generally horizontal direction or vice versa. As the rotor is spun, fluid enters the cuvettes from collection chamber through the inlet channels, which also allow gas in the cuvettes to escape, thus avoiding the creation of bubbles in the cuvette after the cuvettes are filled. The contents are then optically analyzed by passing a light beam horizontally through the cuvette.