The invention relates to a diagnostictape unit with a test tape (12), which can be wound on acoil and consists of a transporting tape (18) and a pluralityof test elements (20), which are mounted thereon.The test elements (20) have a layer of analytical reagents(34), a backing layer (36) carrying the layer ofreagents (34) and a piece of adhesive tape (28), connectingthe backing film (36) with the transporting tape(18). At its front side (24) facing away from the backingfilm (36), the layer of reagents (34) is formed so thatsample substance may be applied. According to the invention,it is proposed that, in conjunction with thelight-transmitting transporting tape (18), the test elements(20) in each case form an optical multilayer systemfor a rear, reflection photometric measurement ofthe reagent layer (34).
