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 pretest considerations, details of the test procedures, and key factors for the interpretation of the results. Guidance is given in annex A for the preparation of materials specifically in relation to the above tests. Guidance on the conduct of supplementary tests which are required specifically for devices used intradermally and in the ocular area is given in annex B. Guidance on the conduct of supplementary tests which may be required for devices used for oral, rectal, penile and vaginal areas is given in annex C.