Abstract: An improved device and method of separating the cellular components of whole blood from plasma or serum and assaying the plasma or serum for a predetermined soluble constituent are disclosed. The device includes a filter pad, that separates the cellular components of whole blood from the serum or plasma, and a test pad, that assays the serum or plasma for a predetermined soluble constituent. The filter pad effectively separates and retains cellular components of the whole blood sample, thereby eliminating assay interference by the cellular components of whole blood.

Abstract: A process and device for quantitative determination of analyte concentrations in liquid samples. The device includes one or more bibulous matrices constructed and arranged to essentially eliminate sample volume sensitivity from analyte determinations. In accordance with the present invention, the device includes one or more test reagent-treated bibulous matrices covered at least partially by an impermeable coating or film. A liquid sample is applied to the uncovered portion of the bibulous matrix such that the liquid sample is metered into the bibulous matrix by the impermeable coating or film. The sample chromatographs through the bibulous matrix until the matrix is saturated with liquid. The process is essentially sample volume independent, providing more uniform and accurate quantitative analyte determinations.