When is a biological indicator considered positive?

A biological indicator is a device used to determine the efficacy of sterilization processes by utilizing microorganisms known for their resistance to specific sterilization methods. A biological indicator is considered positive when growth is present in the ampule after incubation. This indicates that the sterilization process was ineffective, as it failed to eliminate the microorganisms contained within the indicator.

In practical terms, whenever a biological indicator shows signs of growth, it suggests that the sterilization conditions necessary to destroy even the most resilient spores were not met. This can alert sterile processing personnel to re-evaluate the sterilization cycle and take necessary corrective actions to ensure patient safety.

The other options do not reflect the definition of a positive biological indicator. For instance, proper disposal of the biological indicator does not indicate sterilization efficacy, and the absence of growth would confirm that sterilization was successful, not positive. A temperature drop alone does not indicate anything regarding microbial survival or destruction after a sterilization cycle. Thus, growth in the ampule after incubation is the only scenario that definitively identifies a failure in the sterilization process.