This part of ISO 10993 describes the procedure for the assessment of medical devices and their constituent materials with regard to their potential to produce irritation and delayed-type hypersensitivity. This part of ISO 10993 includes a) pretest considerations, b) details of the test procedures, and c) key factors for the interpretation of the results. Instructions are given in annex A for the preparation of materials specifically in relation to the above tests. Supplementary tests which are required specifically for devices used intradermally in the ocular, oral, rectal, penile and vaginal areas are given in annex B.