A multiwell test apparatus formed of a multiwell filter plate having a plurality of wells and a first feeding plate and a second receiver plate is provided. The wells of the multiwell filter plate each have an open bottom surface to which a membrane is attached, at least one first access hole providing access to the feeding/receiver plate below, a pair of alignment pins designed to fit alignment holes in the feeding/receiver plates in a particular arrangement. The first feeding plate is a single well plate or a multiwell plate used solely for feeding. The second receiver plate is a multiwell plate having the same number of wells as the filter plate and aligned so as to receive the wells of the filter plate therein used as the assaying plate. The use of alignment holes in the feeding/receiver plates and alignment posts in the filter plate ensure precise alignment of the plates when together.