Product-Wet Integrity Testing: Cytiva Risk-Based Strategies

By Jeremy Rautenbach, Director, Global Product Management

Integrity testing of sterilizing‑grade final filters is essential to effective contamination control, yet standard water‑based methods do not always reflect real manufacturing conditions. In certain scenarios, using the drug product as the wetting fluid can provide a more representative assessment, minimizing post‑use flushing, avoiding product dilution, and accounting for product–membrane interactions that influence test outcomes. Product‑wet integrity testing supports a risk‑based CCS and addresses a different objective than pre‑use, post‑sterilization integrity testing, which remains focused on contamination risk mitigation.

Industry practice generally follows two approaches to establishing product‑wet limits: applying correction factors to water‑wet specifications or generating cartridge‑scale forward‑flow curves using both product and reference fluids. Discover a rigorous, science‑driven framework that strengthens these approaches by incorporating cross‑checks, clear acceptance criteria, and a clear distinction between tests correlated to microbial retention and those suited for broader system verification.