ISO 10993-12:2021 Biological evaluation of medical devices — Part 12: Sample preparation and reference materials

ISO 10993-12:2021 Biological evaluation of medical devices — Part 12: Sample preparation and reference materials. The ISO 10993 series describes many different biological assay systems. Therefore, the individual parts shall be consulted to ascertain whether these are appropriate for specific test systems. Experimental controls shall he used in biological evaluations carried out in order to either validate a test procedure or compare the results between materials, or both. Depending on the specifications of a particular test, either negative controls, blanks or positive controls, or all three, shall be used. NOTE The same type of control can be applicable to different tests and can allow cross-reference to other established materials and test methods. Additional guidance on the selection of experimental controls is given in Annex A. Use of positive controls for in vivo testing might be affected by animal welfare regulations. 5 Reference materials (RMs) 5.1 General RMs are established by individual laboratories. The extent of chemical, physical and biological characterization is determined by the individual laboratory. Commercially available articles may be used as RMs. NOTE See also ISO Guide 35. CRMs are selected for their high purity, critical characteristics, suitability for the intended purpose and general availability. The critical chemical, physical and biological characteristics shall he determined by collaborative testing in three or more laboratories and made available to the investigator by the distributor. It is desirable for users to obtain a commitment from suppliers of RMs or CRMs stating that these materials will be available to the user for at least five years. A second but less desirable option is for the source of the RM or CRM to publish an “open formulation for the material, i.e. publication of the source materials and details of the processing needed to ensure uniform hatches of the RM. 5.2 Certification of RMs for biological safety testing Qualification of an RM is a procedure that establishes the numerical or qualitative value of the biological response of the material under specified test conditions, ensuring reproducibility of the response either within laboratories or between laboratories, or both. The range of biological responses associated with the material shall be established through laboratory tests. NOTE See also ISO 17034. Suppliers of RMs shall certify the materials. The supplier determines the extent of chemical and physical characterization that is performed. The individual laboratories that use the RM shall identify the biological characterization necessary to qualify an RM for...