Abstract: A stabilized radioimmunoassay product consisting of an antibody protein-bound to the cell wall of a selected bacterium whereby the antibody is irreversibly bound to the protein and remains specific for the antigen against which it was developed. The radioimmunoassay product is also characterized by the fact that the resultant complete product includes a phase of serum protein treatment to isolate the protein sites or other sites of nonspecific reactivity with the labelled antigen such that the non-specific binding of labelled antigen is significantly reduced. Also within the contemplation of the invention is the method of manufacturing the radioimmunoassay product which includes the initial phase of protein binding of the antibody to the selected bacterium and the subsequent serum treatment to isolate previously unutilized protein sites such that when said sites are subsequently exposed to labelled antigen it will be rejected.

Abstract: A rotatable element for use in centrifugal chemical-medical analysis apparatus wherein inlet means is provided in the element near the center of rotation thereof and an outlet is provided near the marginal radially outward edge thereof. A measuring chamber is provided intermediate the inlet and outlet and a conduit is afforded to such chamber from the inlet. A passageway is provided in the element extending radially inwardly from the chamber to a predetermined point or position relative to such chamber, and then to an overflow outlet to thereby define a predetermined filling level for the chamber.Fluid entering the inlet of the rotating element flows simultaneously into the chamber and the passageway under the centrifugal force, the fluid at said predetermined point relative to said measuring chamber overflowing to thereby define the filling level in the chamber.