A method for producing a membrane ring or test strip ring for a diagnostic test device includes an elongate strip that is divided into segments by cuts running transversely to the longitudinal direction of the strip, where the cuts are made only as far as a residual width of the strip so that a material bridge remains intact between the segments adjacent to the cuts (24). The strip is closed by bringing its ends together to form a ring where the cut edges of the cuts running towards the material bridges each enclose an acute angle (α). The ring is inserted into a support structure as a membrane ring or test strip ring for the test device.
