There are several conditions that help define a CSP as a high risk level: when non-sterile ingredients are used in the preparation or when a non-sterile device is used before sterilization; when the preparation is exposed to air of insufficient quality (below ISO class 5), for example when a sterile preservative-free product is exposed to air during storage, it would be classified as high risk; if a non-sterile product is exposed for at least six hours before being sterilized. Before administration to a patient, CSP may not be exposed for no more than 24 hours at controlled room temperature, for no more than 3 days at cold temperatures and for no more than 45 days at freezing conditions (-20°C or less). All non-sterile equipment used in the preparation of the high-risk compound should be rinsed with sterile, pyrogen-free water and drained or dried directly before the preparation begins. CSP subjected to terminal moist heat sterilization must be filtered before or during transfer to the final container through a filter with a nominal pore size no larger than 1.2 µm. Sterilization by filtration must be carried out in an ISO class 5 or higher environment. Some examples of high-risk compounding processes include dissolving nonsterile bulk ingredients to produce solutions that must be terminally sterilized, or when sterile CSP components are mixed in nonsterile containers prior to sterilization. Quality assurance tests need to be carried out to verify the quality of the compounding process. The procedures for these tasks are the same as for the low-risk compounding assessment, except that a media fill test that accurately simulates the most stressful conditions associated with high-risk compounding is performed by staff twice per day. day.