This SOP establishes the requirements for viable surface sampling in sterile compounding areas—including monthly or weekly sampling frequency based on CSP category, use of TSA and SDA media with neutralizers, defined sampling sites in PECs and SECs, incubation at specified temperatures, documentation of CFU counts, corrective actions for alert/action level excursions, and microorganism identification when needed—to ensure contamination control, environmental quality, and compliance with USP <797> and <1116>.