During routine quality assurance of a prevacuum (high vacuum) steam sterilizer, a Bowie-Dick test pack placed in an empty chamber shows an uneven colour change on the indicator sheet inside. What defect does this result indicate?
- A Failure of spore killing due to inadequate temperature
- B Excessive moisture in the steam supply causing wet packs
- C Residual air trapped within the chamber preventing steam penetration ✓
- D Ethylene oxide residue contaminating the chamber
Correct answer: C. Residual air trapped within the chamber preventing steam penetration
Explanation
The Bowie-Dick test is a daily non-biological check run in empty prevacuum sterilizers to detect residual air or air leaks, since trapped air insulates loads from penetrating steam and produces the characteristic uneven indicator pattern. It tests air removal, not microbial kill, so it complements rather than replaces biological indicators. Wetness assessment is done by inspecting packs, and ethylene oxide is irrelevant to a steam sterilizer.
Reference: Ananthanarayan and Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.