A device and method for permitting the separation of plasma or serum from whole blood. The device comprises a matrix of hydrophilic sintered porous material to which at least one red blood cell agglutinating agent has been applied. According to a first method of using the device, a sample of whole blood is applied to a first end of the matrix and the red blood cells within the sample come in contact with the agglutinating agents present in the matrix. The blood cells agglutinate, and are entrapped in the interstices of the matrix, while substantially blood-cell-free serum or plasma accumulates near the outlet of the device. A filter means in liquid receiving relationship with the matrix functions to wick the serum of plasma from the matrix.
According to an alternative aspect of the invention, a filter means in liquid receiving relationship with the outlet of the matrix functions to retain any blood cells which pass through the matrix as the filter means wicks the plasma or serum from the matrix. Additional agglutinating agents may be incorporated within the filter means to facilitate retention of blood cells which pass through the matrix.
Another aspect of the present invention involves a device for the measurement of a serum or plasma sample, utilizing a matrix of sintered porous material, such as sintered glass, sintered steel, sintered ceramics, sintered plastics, and equivalents thereof. The matrix is characterized by a reproducible fluid uptake capacity proportional to the fixed dimensions of said matrix, a minimal reactivity with plasma or serum components, and a hydrophilic internal surface which enables the matrix to collect and retain a predetermined volume of sample for analysis.