Abstract: The method described coats the interior of a tube-like support with the binding partner of the analyte. Analyte and anti-analyte-label conjugate are added. When the tube-like support is rotated end-over-end, the thin layer of analyte and conjugate readily react with the binding partners to form an immobilized label complex. When rotation stops, the reaction quenches to provide precise timing. The label complex is released and measured.

Abstract: An improved heterogeneous immunoassay is provided which includes the utilization of support materials capable of reversible immobilization of proteinaceous binding partners of biological material of interest and the removal of labeled complexes from these supports through the use of release reagents permitting the subsequent solution phase determination of the amount of label.

Abstract: A highly sensitive and rapid method for quantitatively assaying analytes in liquid media by directly measuring changes in particle size distribution of reagent particles having analyte insolubilized thereon in a system undergoing antibody-induced aggregation has been developed. The amount of analyte initially present can be determined by measuring the change in the distribution of particle size with time, the concentration of a particular size particle at a given time, the rate of formation of a particular size particle, or the steady-state maximum concentration for a particular size particle.

Abstract: Novel particle reagents for light scattering immunoassays are provided. The particle reagents are high refractive index shell-core polymers covalently bonded to compounds of biological interest or analogs thereof. A method of measuring unknown concentrations of these compounds of biological interest by measuring changes in turbidity caused by particle agglutination or its inhibition is also provided.