5 reagents, namely, nucleic acids, antibodies, antigens, lipids, proteins, polynucleotides, polypeptides and small chemical molecules, all labeled with metallic light-scattering particles, for clinical or medical laboratory use; metallic light-scattering particles for use as labels for small molecules for clinical or medical laboratory use; assay kits comprised of solutions, buffers, reagents, substrates, particles and diluents for detection of target molecules, for clinical or medical laboratory use