Automated direct serum radioassay

Claim 1

In a process for automated radioassay of a ligand sample by flowing the sample through a chamber containing an immobilized binder composed of a solid substrate and binder specific to the ligand and wherein the sample contains proteins tending to plug the substrate, the improvement comprising: diluting the sample to a consistency for free unplugged flow through the immobilized binder; preincubating the sample with a binder specific to the ligand in said sample being assayed together with a known amount of a radioactive labeled ligand to form a mixture including (a) unlabeled ligand bound to the binder, (b) labeled ligand bound to the binder, (c) free unbound unlabeled ligand, and (d) free unbound labeled ligand; providing a chamber containing a binder specific to the ligand supported on a solid substrate to bind free unbound labeled and unlabeled ligand; flowing said mixture through said chamber to bind free unbound labeled and unlabeled ligand to the solid supported binder in the chamber with the bound labeled and unlabeled ligand passing through the chamber; flowing an eluting solution through said chamber to effect release of labeled and unlabeled ligand from the solid supported binder in the chamber; counting the radioactivity of at least one or both of the labeled ligand which passed through the chamber and the labeled ligand eluted from the chamber to determine the quantity of the ligand sought to be assayed in said sample; and rinsing the chamber for subsequent assays of other samples of the same ligand.