| Severity | 4 | 4 | If the filter fails or microbial ingress happens, it has a major effect in both cases |
| Frequency | 3 | 2 | Microbial ingress into the downstream side has occurred, for this reason the downstream side is commonly held under pressure after steam sterilization. This overpressure is replaced by atmospheric pressure during the pre-use test (3). Since steam sterilized downstream processes are commonly held at overpressure the likelihood of ingress is lower (2). |
| Detectability | 3 | 1 | If there is a microbial ingress due to downstream manipulation, when the test is performed, it will not be detected (3). If the filter is flawed due to the steam sterilization process it will be readily detected by the post-use test (1). |
| Risk level | 36 | 8 | Risk assessment would not recommend a pre-use/post-sterilization test. |