A hand-held assay device measuring chemiluminescence generated by as ample of
ATP
or other entity capable of chemically reacting to generate photoluminescence includes
a photodiode detecting light which is emitted from the sample to produce a sample
signal, another photodiode generating a reference signal in response to environmental
changes, switched integrators amplifying the sensor signal over a controllable
integration time to detect an output signal indicative of the presence of the sample.
