The ASTM F 2475-20 Standard Guidance provides a framework for evaluating the biocompatibility of medical apparatus Encasement materials. It emphasizes the importance of the compatibility of Encasement materials with medical devices in meeting regulatory requirements, and states that the safe use of these materials in humans needs to be evaluated to ensure that they do not negatively affect the physical, chemical or biological properties of the device. The Guidance includes methods for biocompatibility testing of Encasement materials that come into direct or indirect contact with patients, but does not apply to secondary or tertiary Encasement materials. It also requires device manufacturers to consider Encasement interactions with devices and, if necessary, conduct appropriate biocompatibility testing to ensure compliance with international standards and regulatory requirements.