Abstract: Methods are disclosed for separating a component of interest from a mixture containing the component of interest and other components. The method comprises contacting a first liquid medium containing the component of interest and other components with a second liquid medium that is of different density than and/or of different viscosity than the first liquid medium. The contact is carried out in such a way that mixing of the media is minimized or avoided. The component of interest is bound to magnetic particles. The contacted first liquid medium and second liquid medium are subjected to a magnetic field gradient to allow the magnetic particles to migrate into the second liquid medium and separation of the component of interest from other components is realized. Also disclosed are assays employing the present method. Kits for carrying out the present method and assays are also disclosed.

Abstract: Methods are disclosed for separating a component of interest from a mixture containing the component of interest and other components. The method comprises contacting a first liquid medium containing the component of interest and other components with a second liquid medium that is of different density than and/or of different viscosity than the first liquid medium. The contact is carried out in such a way that mixing of the media is minimized or avoided. The component of interest is bound to magnetic particles. The contacted first liquid medium and second liquid medium are subjected to a magnetic field gradient to allow the magnetic particles to migrate into the second liquid medium and separation of the component of interest from other components is realized. Also disclosed are assays employing the present method. Kits for carrying out the present method and assays are also disclosed.

Abstract: A method for determining the presence of a specific binding member bound to first particles in a liquid medium is disclosed. The method comprises providing in combination (1) a liquid medium suspected of containing a specific binding member bound to first particles, (2) means for agglutinating the first particles in relation to the presence of the specific binding member, and (3) second particles having the same or a different specific binding member for said means for agglutinating bound thereto, thereby providing for said means to agglutinate the second particles. Agglutination of the first and second particles are separately detectible and distinguishable by spectroscopic measurement. The medium is incubated and agglutination of each of the particles is determined spectroscopically without separating the first and second particles.