Abstract: Diluent compositions for preparing specimens for immunoassay contain effective amounts of salt and non-ionic surfactants to inactivate viruses in the specimens and improve the sensitivity and specificity of the immunoassays; said diluents having some strengths of from about 21 to about 35 mS/cm and comprising 0.05 to 1% non-ionic surfactants, along with other conventional ingredients. The invention relates as well to immunoassay procedures using the novel diluents.

Abstract: In an affinity detection apparatus wherein the specific recognition of a first chemical for a second chemical is used to identify the presence of either, and being of the type normally including a receptical tray having at least one well sized to hold both an insertable member and a solution containing the first of said chemicals, andAn insertable member coated with the second chemical, the improvement comprising:The coated member and well being complimentary shaped so as to define a first thin passageway between the member and well along substantially all the well periphery.