Cell-therapy manufacturers are adapting quality systems to address particulate inspection challenges as clearer regulatory guidance remains limited. CMC consultants say particulates in cell-containing products often come from single-use equipment and can be hard to visually assess because final materials are stored in opaque freezing bags. To manage compliance, some companies run processes with formulation buffer minus cells to characterize visible and sub-visible particles, then extrapolate to full runs. Testing approaches reference USP chapters 790 and 788 (and corresponding EU visual-inspection guidance) depending on route and risk profile.