Method and compositions are provided for performing homogeneous immunoassays. The method involves having a signal producing system, which provides a detectable signal, which system includes a macromolecular member. The determination of the analyte, which is a member of a specific binding pair consisting of a ligand and its homologous receptor, is performed by creating an extensive matrix in the assay medium by having in the assay medium in addition to the analyte, ligand labeled with one of the members of the signal producing system, antiligand either present as the analyte or added, a polyvalent receptor for antiligand, the macromolecular member of the signal producing system, and any additional members of the signal producing system. The labeled ligand, antiligand, and polyvalent receptor for the antiligand create a matrix which modulates, e.g. inhibits, the approach of the macromolecular member of the signal producing system to the labeled ligand. The extent and degree of formation of the matrix is dependent upon the concentration of the analyte in the medium. By comparing the signal from an assay medium having an unknown amount of analyte, with a signal obtained from an assay medium having a known amount of analyte, the amount of analyte in the unknown sample may be determined qualitatively or quantitatively.Kits are provided having predetermined amounts of the various reagents to allow for enhanced sensitivity of the method.