The starting material, formulation, processing variations, sterilization, packaging, shipping, and aging all have effects on the biocompatibility of the device.
During the data review the characterization of toxicological hazards as well as other biological reactions to medical devices.
General review of literature on toxicology data of materials  and test data from biological tests.
Testing should not be done if the risks are acceptable.  Testing should not be done if the risks are unacceptable.  Therefore testing should be done to answer the unanswered questions left by the chemical characterization and literature review.
A review of the testing results should be conducted.  Is the data sufficient.  It should document how the conclusion of acceptable risk was determined in a transparent, focused and precise manner and fully discussed.
Compounds that leach out of medical devices are rarely single entities and the  combination of compounds that exist could increase or decrease the toxicity of an individual chemical constituent.  Very rarely is there data available for chemical mixtures.
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