In a multiplexed assay method carried out in solution, wherein the solution contains nucleic acid targets and, wherein several different types of oligonucleotide probes, each type having a different sequence in a region designated as a target binding domain, are used to detect the nucleic acid targets, said assay method including a method for increasing the effective concentration of the nucleic acid targets at the surface of a bead to which the oligonucleotide probes are bound, by one or more of the following steps: adjusting assay conditions so as to increase the effective concentration of the targets available for binding to the probes, by one or more of the following: (i) selecting a particular probe density on the surface of the bead; (ii) selecting a solution having an ionic strength greater than a threshold; (ii) selecting a target domain of a size less than a threshold; or (iii) selecting target domains within a specified proximity to a terminal end of the targets.