Abstract: An improved method for performing an in vitro diagnostic test is provided. The method utilizes a solid phase device having a fixed component immobilized on its surface which is in contact with a fluid sample when inserted therein. The improvement resides in utilizing a receptacle, into which the device is inserted, having the same fixed component immobilized on the inner surface of the receptacle. The test is performed by placing a fluid sample, having a mobile component reactive with the fixed component, into the receptacle and in contact with the insert for a period of time and measuring a change which is a function of the concentration of the mobile component.

Abstract: A method and apparatus for conducting chemical reactions at a liquid-solid interface wherein a reaction component is fixed on the surface of a solid phase immersed in a liquid phase containing a freely diffusing, mobile reaction component. The apparatus comprises a substantially smooth-surfaced matrix of appropriate geometrical configuration designed to provide a large surface to volume ratio, a short transfer distance from the mobile component to the fixed component distributed on the solid phase surface and to drain freely upon removal from the reaction liquid.

Abstract: A method and solid phase matrix is disclosed which has special utility for use in conjunction with automatic pipetting apparatus for conducting reactions at a liquid-solid interface. A reaction component is fixed on the surface of the solid phase matrix which is wetted by a liquid phase containing a freely diffusing, mobile component. The matrix is comprised of a support surface to which are attached a plurality of inwardly projecting fins. The innermost extension of the fins defines a centrally located well into which an automatic pipetting apparatus may be inserted. The method may be used for qualitative or quantitative determinations of the mobile component contained in a liquid which wets the solid phase matrix.