To ensure that sterilizing grade filters in aseptic processing worked as required, such filters are integrity tested. Integrity tests, like the bubble point, diffusive flow or pressure hold test, are non-destructive tests, which are correlated to a destructive bacteria challenge test. This correlation verifies the integrity test limits the filters have to pass. integrity tests are required by regulatory authorities. The post filtration integrity test is a must, pre filtration integrity testing is recommended. The different tests have specific limitations therefore there is no overall, best integrity test, which can be utilized for every filtration system.