Abstract: A stabilized alcohol solution of reducing salt formulations has been developed and applied to the development of such agents as a radiolabeled liver scanning agent comprising colloids of technetium-99m and a reducing agent selected from the group of SnCl.sub.2, TiCl.sub.3, CrCl.sub.2 and FeCl.sub.2 and other salts, with or without a stabilizing agent, a bone scanning agent comprising a phosphate complex and a lung scanning agent comprising macro aggregated albumin.

Abstract: A method for direct radioimmunoassay of antigens or their associated antibodies utilizing a coated test apparatus comprising adding a serum to be tested for an antigen to test apparatus coated with its antibody; incubating the tubes for from 0.5 to 42 hours; aspirating the contents and washing the same with a Tris-HCl and sodium azide mixture; adding purified I.sup.125 labeled antibody into the tube and incubating for from 1 to 24 hours; aspirating and washing the contents; and counting the tube for I.sup.125 radiation. A similar assay for the antibody may be conducted utilizing an antigen coated apparatus and I.sup.125 labeled antigen. The method for coating these apparatus such as tubes comprises adding the antigen or antibody solution in a Tris-HCl, sodium azide solution into a suitable test tube or well, incubating the tubes at room temperature, aspirating and washing the contents and storing at from between 2.degree. and 25.degree. C. until use.