ANSI AAMI ISO 10993-4-2002 pdf download
ANSI AAMI ISO 10993-4-2002 pdf download.Biological evaluation of medical devices
6.1.1 Figure 1 illustrates a decision tree that can be used to determine whether testing for interaction with blood is necessary. Blood interactions can be classified into five categories based on the primary process or system being measured. Tables 1 and 2 list examples of devices which contact circulating blood and the categories of testing appropriate to the device. NOTE—Since this is a horizontal International Standard, good rationales can be developed to justify the choice of category based on the device being characterized. Thombosis testing is frequently the preferred method for device characterization. In many cases, rationales can be used to substitute some combination of coagulation, platelets, hematology, and complement system testing for thrombosis testing. For medical devices where a specific International Standard (vertical standard) exists, the biological evaluation requirements and test methods set forth in that vertical standard shall take precedence over the general requirements suggested in this part of ISO 1 0993.
6.1.2 Where possible, tests shall use an appropriate model or system which simulates the geometry and conditions of contact of the device with blood during clinical applications, including duration of contact, temperature, sterile condition, and flow conditions. For devices of defined geometry, the ratio of test parameter (concentration per unit volume) to exposed surface area (cm 2 ) shall be evaluated. Only blood-contacting parts should be tested. The selected methods and parameters should be in accordance with the current state of the art.
6.1.3 Controls shall be used unless their omission can be justified. Where possible, testing should include a relevant device already in clinical use or a well-characterized reference materials [7] . Reference materials used should include negative and positive controls. All materials and devices tested shall meet all quality control and quality assurance specifications of the manufacturer and test laboratory. All materials and devices tested shall be identified as to source, manufacturer, grade, and type.
6.1.4 Testing of materials which are candidates for components of a device may be conducted for screening purposes. However, such preliminary tests do not serve as a substitute for the requirement that the complete device or device component be tested under conditions which simulate or exaggerate clinical application. 6.1.5 Tests which do not simulate the conditions of a device during use may not predict accurately the nature of the blood/device interactions which can occur during clinical applications. For example, some short-term in vitro or ex vivo tests are poor predictors of long-term in vivo blood/device interactions [25], [26] .
6.1.6 It follows from the above that devices whose intended use is ex vivo (external communication) should be tested ex vivo and devices whose intended use is in vivo (implants) should be tested in vivo in an animal model simulating as closely as possible conditions of clinical use.
6.1.7 In vitro tests are regarded as useful in screening external communicating devices or implants, but may not be accurate predictors of blood/device interactions occurring upon prolonged or repeated exposure or permanent contact (see 6.3.1 ). Devices intended for non-contact use only do not require evaluation of blood/device interactions. Devices which come into very brief contact with circulating blood (e.g., lancets, hypodermic needles, capillary tubes) generally do not require blood/device interaction testing.
6.1.8 The two recommendations in 6.1 .5 and 6.1 .6, together with clause 5, Figure 1 , and Table 2, serve as a guide for the selection of tests listed in 6.2.1 .
6.1.9 Disposable laboratory equipment used for the collection of blood and performance of in vitro tests on blood shall be evaluated to ascertain that there is no significant interference with the test being performed.
6.1.10 If tests are selected in the manner described and testing is conducted under conditions which simulate clinical applications, the results of such testing have the greatest probability of predicting clinical performance of devices. However, species differences and other factors may limit the predictability of any test.
6.1.11 Because of species’ differences in blood reactivity, human blood should be used where possible. When animal models are necessary, for example, for evaluation of devices used for prolonged or repeated exposure or permanent contact, species’ differences in blood reactivity shall be considered. Blood values and reactivity in humans and non-human primates are very similar [26] . The use of animals such as the rabbit, pig, calf, sheep, or dog may also yield satisfactory results.
