Abstract: An improved beta activity counter is disclosed which provides for counting plural, preferably even numbers of, samples simultaneously, while allowing automated handling of sample vial racks which are different widths are multiples of the number of simultaneous testing cells. The number of indexing steps needed per rack are adjusted automatically according to the number of vials that each rack will hold. Quench counting of adjacent samples simultaneously via use of one external source is also provided.
Abstract: Compounds useful in a simultaneous multiple assay for analytes such as steroids, proteins, peptides, carbohydrates or drugs. The compound or compounds are prepared by labelling an individual analyte with a radioisotope through a chelating agent to form a coordinated compound. The assay uses one or more chelated labelled analytes with one or more labelled analytes wherein each radioisotope is different.