An immunoassay for the detection of an analyte in a sample includes a plurality of moieties capable of binding to the analyte. Capture moieties, which are not specific for the same epitope, are bound to a solid substrate, and at least one epitope-specific detection moiety is bound to a detectable marker. The detectable marker is a large particle marker having a particle size of ≥50 nm and ≤5000 nm.