Body fluid testing device for analyzing a body fluid, comprising: a test media tape (30) adapted to collect the body fluid, said test media tape comprising a tape and test media portions, wherein a free tape portion without the test medium is located between successive test media portions, said testing device further comprising a supply portion wherein said supply portion comprises a housing in which uncontaminated test media tape is contained, said housing further having an opening for withdrawing test media tape from the housing, the testing device further having a sealing means for closing said opening against the surrounding, wherein a free tape portion of said test media tape is located between a wall of the housing and the sealing means when said sealing means closes said opening. The application further concerns a test media cassette with sealing means and a method for providing test media while holding them sealed against humidity during on board storage.