Abstract: An apparatus is provided for holding down membrane elements in respective wells of a multiwell plate, which has, at its top side, respective openings of the respective wells. The apparatus has, at its upper region, a support structure having respective openings, and respective corresponding retention elements which extend downwards from the respective openings of the support structure, so that respective retention elements protrude into respective wells when the support structure has been placed onto the top side of the multiwell plate. A retention element has multiple webs which extend downwards from the support structure and the ends of which are connected to one another at a bottom side of the apparatus by means of a connection element.

Abstract: An elongated incubation trough has an indentation open toward a top end as well as a bottom. The indentation has a first receiving area to receive an elongated test strip as well as a second receiving area to receive an end section of a fluid line. The second receiving area is in fluidic communication with the first receiving area. A maximum width of the second receiving area at bottom height is greater than a maximum width of the first receiving area at bottom height.

Abstract: An elongated incubation trough has an indentation open toward a top end as well as a bottom. The indentation has a first receiving area to receive an elongated test strip as well as a second receiving area to receive an end section of a fluid line. The second receiving area is in fluidic communication with the first receiving area. A maximum width of the second receiving area at bottom height is greater than a maximum width of the first receiving area at bottom height.