Separation, washing and determination of analytes tagged with magnetic particles

Method for detecting a material of interest, usually an antibody or an antigen on a red blood cell, in a liquid, by observing the potential antigen/antibody reaction products in a novel way. Reaction products are deposited on a magnetic substrate and will exhibit different properties depending upon whether or not the antigen/antibody reaction has taken place. An antigen/antibody reaction product adheres tenaciously to itself and the substrate while the deposit of any unreacted magnetically tagged material is weakly adhering and easily disrupted and dislodged under a disruptive force which would be insufficient to dislodge the reacted deposit. This difference in cohesive property provides the means by which a positive result is distinguished from a negative result.