Abstract: Methods for detecting the presence or absence of, and for quantifying, one set of cells in a mixed cell population of at least two sets of cells especially Rh positive cells in a mixed population with Rh negative cells, as is found in a fetal maternal hemorrhage (FMH). The magnetic particles coated with anti-D antibodies are reacted with the Rh positive fetal cells in Rh negative maternal blood followed by a specific separation and quantifying technique. Gravitational forces or magnetic forces are used to move reacted magnetic particles to isolate, distinguish and quantify cells differentiated by antigenic composition. Rh positive cell volume is correlated to the volume of the original blood sample as an indication of the number of doses of RhIG needed to be administered to the mother to prevent subsequent Rh immunization.

Abstract: Methods for separating, cells, particles, or other molecules of interest (MOI) from unwanted materials not of interest (MNOI). by forced movement of MOI into certain zones having properties which deter the entry of unwanted materials. MOI are tagged with magnetic particles and moved with a magnetic field through a fluid, or zones, of higher specific gravity that prevents, unwanted less dense materials from entering. Buoyant or other forces are used to remove any unbound material from the complexes with ASG before reading. Readable labels include the magnetic particle tagged complex itself, and other labels such as enzymes, chemiluminescent materials, radioactive isotopes, chromogenic and fluorogenic substrates and other labels may be used. The invention applies to many assays, diagnostic tests, separative procedures and chemical syntheses.

Abstract: 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.

Abstract: Methods for separating, in a continuous, multizone fluid medium, cells, particles, or other molecules of interest (MOI) from associated or contaminating unwanted materials not of interest (MNOI). The invention involves forced movement of MOI into certain zones having properties which deter the entry of unwanted materials. Differential movement of MOI and MNOI occurs by active counterforces that move MNOI but not MOI. MOI are tagged with magnetic particles and moved with a magnetic field through a fluid, or zones, of higher specific gravity that prevents, by flotation counterforce, unwanted less dense materials from entering. Surfaces specifically coated with reactants are reactive with the MOI in the tagged magnetic particle complex and of buoyant or other forces are used to remove any unbound material from the surface before reading.

Abstract: Detection of the presence or absence of, RH positive cells in a mixed population with Rh negative cells, as is found in a fetal maternal hemorrhage (FMH). The novel methods utilize gravitational forces or applying magnetic forces to reactive magnetic particles to isolate, distinguish and quantify cells. Particles aggregate and are pulled or settle by gravity through a transparent separating solution into a measuring zone where the volume of Rh positive cells can be measured. Rh positive cell volume is correlated to the volume of the original blood sample as an indication of the number of doses of RhIG needed to be administered to the mother to prevent subsequent Rh immunization.