Abstract: A diagnostic microscope slide includes a base plate and a cover plate. The base plate has an upper surface from which a plurality of ring-shaped walls extend, each surrounding a shallow well for holding a biological sample. The portions of the base plate directly beneath each sample well form a thin transparent bottom lens that defines the bottom of that sample well. The cover plate includes an upper surface and a lower surface having a plurality of cover lens recesses into which the respective ring shaped walls extend when the cover plate is in place on the base plate. The top of each cover plate recess in the cover plate is defined by a thin transparent cover lens. The bottom surface of each cover lens rests on and forms a seal with the upper rim surface of the ring shaped wall, thereby preventing migration of biological sample material from one sample well to another.