Abstract: Dry, pelletized reagents are described which rapidly reconstitute into active reagent solutions when contacted with an appropriate liquid sample or other appropriate solution, including heterogeneous reagent pellets made from two or more separate reagent solutions in such manner that components in the separate reagent solutions which will normally react with each other in solution do not substantially react. Also described are reagent dispenser packages and assay devices containing dry pelletized reagents.

Abstract: An assay system including reagents and devices for conducting rapid, high sensitivity analyte assays, including multiplexed assays, is described. The reagents and devices are adapted for performing time-resolved signal detection with low background due to non-specific binding. Also described are apparatus for use in measuring a luminescent property of a sample. The apparatus can use light emitting diodes for emitting radiation to excite the sample, under the control of a control signal. A signal generator generates the control signal for modulating the intensity of the emitted radiation. The control signal has a first component at a first frequency with a period that is less than, or of the same order as, an expected characteristic time constant of the luminescent property. The control signal has a second component at a second frequency with a period that is greater than the expected characteristic time constant of the luminescent property.