Biological Indicator Testing
Microtest performs definitive biological indicator testing for sterilization validation and lot release to ensure compliance with USP requirements.
Biological indicators (BI) are filter strips impregnated with Bacillus atrophaeus(formerly called Bacillus subtilis) spores. These are included among medical product samples and tested for population and resistivity. BIs are then subjected to the customer’s preferred sterilization method — usually via ethylene oxide (EO) gas.
Finally, BI strips are tested for remaining presence of this spore-borne biological indicator. Since such spores are usually challenging to sterilize, their absence in the final sample validates the method or lot and determines sterility assurance levels.
We take extreme care to minimize the chance of false positive readings, which can trigger expensive retesting or delay release. Additionally, Microtest often advises customers on such factors as avoiding excessive dryness in lot shipment or storage, which can considerably increase biologic indicator resistance.
Microtest utilizes the state-of-the-art Microseq gene sequencer for BI identification and OOS investigation.