The invention concerns a process for producing a membrane ring or test stripringfor a diagnostic test device in which a) an elongate strip (26) is dividedintosegments (20) by cuts (24) running transversely to the longitudinal directionof thestrip, b) wherein the cuts (24) are made only as far as a residual width ofthe strip(26) so that a material bridge (38) remains intact between the segments (20)adjacent to the cuts (24), c) the strip (26) is closed by bringing its endstogether toform a ring, wherein the cut edges of the cuts (24) running towards thematerialbridges (38) each enclose an acute angle (a), d) the ring (22) is insertedinto asupport structure (12) as a membrane ring or test strip ring for the testdevice.
