Disclosed is an assay device to determine the presence of at least one analyte of interest in a liquid sample, the device comprising means for generating a first signal (the ‘test’ signal) which indicates the presence and/or amount of analyte of interest in the sample; and means for generating a second signal, the generation of which second signal indicates both (a) the test has been successfully conducted, and that (b) sufficient time has elapsed following contact of the assay device with the liquid sample for the test to be read and the first signal to have been properly generated.