This presentation has been recorded during BPI EUROPE Digital Week 2021.

When a developed virus filtration process is validated by viral clearance testing, the addition of a virus spike for just this purpose can lead to disappointing results. Not achieving processing targets like throughput or viral clearance targets such as log reduction can cause development delay and cost increases. Problems can be produced by the virus spike itself, product stability, clearance testing methods, and complications due to prefilter implementation. Process development and viral clearance laboratories have to communicate in significant detail to ensure successful clearance testing that suitably mimics the final production process. We give some guidance and examples of what can be done to mitigate the occurrence of unsatisfactory results and get to the maximum achievable outcome during a viral clearance study for a batch process with prefiltration. We also take a brief look at how the findings and recommendations could be translated to a continuous process setting.