The study shows that the new approach, as proposed by CEN TC102 wg4, for the development of a test method for the determination the microbial barrier properties of packaging materials for medical devices does not give the expected advances over the in 1990 presented LGM test method (RIVM-report 919000001, June 1990). The material qualification obtained by means of a materials test does not provide any relevant information about the expected performance of the material when formed into a final pack. The authors recognize the desirability for a materials test in the production of medical devices but the results show that the design of every type of packaging concept must be validated by means of a final pack test. This does however not exclude the use of a materials test for the purpose of in process control in the field of production. Once both the concept and the forming of the pack is validated a materials test will be very usefull to check whether the quality of the wrapping material is identical to the quality of the materials used in the validated packaging concept.