biological indicator
Also written as: BI — Biological Indicator
Test device containing viable microorganisms used to monitor sterilization process efficacy.
Full Definition
A biological indicator (BI) is a test system containing viable microorganisms exhibiting a defined resistance to a specified sterilization process. BIs provide the most stringent test of sterilization efficacy by using living organisms rather than chemical or physical parameters. The standard organism for steam sterilization is Geobacillus stearothermophilus, chosen for its high heat resistance. BIs are used for routine monitoring, load release, and process validation. Results typically require 24-48 hours for traditional culture methods, though rapid-readout BIs can provide results within hours.
Usage
Usage note: Distinguish from chemical indicators which only show exposure. 'Spore test' is acceptable informal usage.
In Context
- "Weekly biological indicator testing confirmed the steam sterilizer's continued efficacy." — Quality assurance report
- "The positive biological indicator result triggered an immediate recall of potentially non-sterile instruments." — Incident investigation report