Users of biological indicators (BIs) need to have an appropriate level of knowledge of the product and its intended use prior to purchase. Once achieved, users also need to have confidence in the quality of the product received prior to placing it into use. There are two general methods for gaining confidence in product quality, 1) performing a quality audit(s) of the manufacturer to verify compliance to relevant standards/regulations, and 2) performing quality testing on each incoming BI lot. There are several important BI qualities that can be evaluated by second/third parties including, BI spore count (population), BI resistance to the process (D-value or Survival/Kill), and identity/purity of the test organism.
This edition of Spore News will cover the various aspects of population verification. BIs contain live organisms that are shipped long distances, and as such, verification of the population (as an incoming inspection activity) is recommended. Verification of population is not a complex task; however, it is important to perform these assays per the manufacturer’s instructions to achieve meaningful results. Relevant standards and other resources are provided below.
ISO 11138-7:2019 Sterilization of health care products – Biological indicators – Part 7: Guidance for the selection, use and interpretation of results
6.1.4 When the user has established a high level of confidence in the supplier (see 6.1.3), the testing performed by the user can be minimal. At a minimum, the user should have a mechanism to ensure that a shipment of biological indicators contains all agreed-upon documentation, such as appropriate label information, packet inserts, storage and handling instructions, etc. There should be a mechanism to ensure that the BI supplier continues to maintain the expected quality standards, such as a BI supplier or BI manufacturer’s declaration of conformity to standards. If the user has not established the supplier relationship required to be ensured of consistent biological indicator performance, additional testing could be necessary until an appropriate assurance can be established that the biological indicators meet the BI manufacturer’s label claim and/or user requirements.
6.1.5 Testing by the user, if deemed necessary, can consist of population assays and defined resistance tests such as D value or survival-kill time on samples from each new batch of biological indicators received (see also 8.6 and Clause 11). Testing should be conducted under exact conditions specified by the manufacturer. Provided that the biological indicator manufacturer produces the based upon detailed standard specifications, i.e., the ISO 11138 series, and the user uses the biological indicator as intended by the biological indicator manufacturer, testing of the resistance characteristics by the user is considered unnecessary.
11.2.1 . . . When tested, the population should be between 50% and 300% of the nominal population. The BI population as labeled by the manufacturer should be used in all calculations following verification. The biological indicator manufacturer should be consulted to ensure that the same techniques and procedures are used because variations in testing procedures can affect the population determination results. ISO 11138-1 requires the manufacturer to provide this information on request.
11.2.5 The user should follow the manufacturer’s recommended procedures for recovery to ensure comparable results.
SN075-V1