Abstract: Disclosed herein is an apparatus and process for conducting ligand receptor assays. The apparatus comprises a first member which is a membrane or a filter to which is bound a receptor for the ligand or which is capable of extracting cells carrying the ligand from a fluid sample. The apparatus further comprises a second member which is composed of absorbent material which acts when in contact with the first member to induce flow through the first member when a fluid sample is added to it. The apparatus is used to conduct assays by applying a sample to the upper surface of the first member to bind ligand in the sample by means of receptor fixed to the first member or, in certain cases, by extracting cellular material which has ligand associated with it. Addition of the sample is typically followed by addition of labeled antibody against the antigen being assayed followed by a washing step to remove unbound labeled receptor.

Abstract: Disclosed herein is an apparatus and process for conducting immunoassays. The apparatus comprises a first member which is a membrane or a filter to which is bound an antibody, typically a monoclonal antibody, or which is capable of extracting cells from a fluid sample. The apparatus further comprises a second member which is composed of absorbent material which acts when in contact with the first member to induce flow through the first member when a fluid sample is added to it. The apparatus is used to conduct immunoassays by applying a sample to the upper surface of the first member to bind antigen in the sample by means of antibody fixed to the first member or, in certain cases, by extracting cellular material which has antigen associated with it. Addition of the sample is followed by addition of labeled antibody against the antigen being assayed followed by a washing step to remove unbound labeled antibody.