What is the primary purpose of biological indicators in sterilization monitoring?

• A. To validate sterilization efficacy by confirming destruction of resistant spores.
• B. To verify exposure temperature only.
• C. To confirm operator technique.
• D. To test chemical indicators.

Answer: (A)

Biological indicators are used to confirm that a sterilization cycle actually destroys microorganisms, including the most resistant spores. They contain a known population of spores and are placed in or with a load to be sterilized. After the cycle, the indicator is incubated to see if any spores survived and grew. If growth occurs, the sterilization cycle did not achieve sterility for that load; if there is no growth, the cycle effectively destroyed the spores, demonstrating that the process worked under those conditions. This direct evidence of sterility is why biological indicators are the primary method for validating sterilization efficacy. They specifically test the outcome of the entire process, unlike chemical indicators, which only verify exposure to certain parameters, or indicators that assess technique.