摘要 |
<p>A system (30) for assaying a fluid sample. The system (30) comprising a lens (33) capable of focussing both excitation and fluorescent radiation, a fluid-flow conducting conduit (42) being provided in the lens (33) extending transversely of the optical axis of and through the focal region of the latter. At least one mechanical screen (38A, 38B) is disposed adjacent the focal region in the conduit (42) to arrest passage of beads (40) as a function of bead diameter. The beads (40) are precoated with at least a moiety of a ligand/conjugated complex and preferably transparent to both the excitation and fluorescent radiation.</p> |