Cell-therapy manufacturers are adapting to ambiguous U.S. regulatory guidance on particulates by changing how they demonstrate visible and sub-visible particulate control during manufacturing. A CMC consultant described a common challenge: cell-containing products are often stored in opaque freezing bags, making visual inspection more difficult. The approach highlighted involves running the process using formulation buffer without cells, then extrapolating particulate results to the full cell process. The consultant also noted testing strategies aligned with United States Pharmacopeia chapters for visible particulates and injections and for sub-visible particles, with EU guidance sometimes used as supporting reference. The work emphasizes that testing stringency may vary by administration route, since stricter particulate limits apply to delivery methods such as intrathecal injections.