The diagnostic tape unit is made of a transporting tape (18) and multiple test elements having a layer of analytical reagents (34), a backing layer (36) carrying the layer of reagents and a piece of adhesive tape (28), connecting the backing film with the transporting tape. The test element is in conjunction with an optical multilayer system for a rear, reflection photometric measurement of the reagent layer. An independent claim is included for a diagnostic measurement system for blood sugar test.