Disposable container configured to produce uniform signal

There is disclosed a container (10) for storing a reagent and then for reacting the reagent to produce a signal representative of the presence of an analyte, or of the amount of that analyte. The container is disposable and comprises at least one compartment (12,14,16) having an upper portion (20) and a lower portion (30). The upper portion comprises a stored reagent and means for retaining for observation on an indicator surface (24) a reaction product of such reagent following a reaction of the reagent with a liquid sample. The lower portion (30) includes means (32) for absorbing liquid extracted from the upper portion through the retaining means. The absorbing means is configured with a shape (60,61) that contacts the retaining means only at locations spaced inwardly away from at least two of the side walls (40,50) of the upper portion, whereby the reaction product of the liquid sample and the reagent is induced to flow into the retaining means away from the two side walls to produce a uniform signal.