Brief on Bowie-Dick test:

  • Bowie-Dick (Air-Removal) tests assess the effectiveness of pre-vacuum sterilizers by verifying adequate air removal from the sterilizer chamber.
  • It might be wondering if Bowie-Dick tests are still necessary in sterilizers that feature programmed leak testing despite the fact that these air removal tests have been enhanced over time.
  • It must first comprehend why it is crucial to eliminate air from the sterilizer in order to completely appreciate why this test is still crucial today.
  • It’s common to refer to the air within a steam sterilizer as a non-condensable gas (NCG).  Non-condensable gases, as the name suggests, do not condense when in contact with a colder object.
  • These gases serve as a barrier between the steam and the object, possibly protecting microorganisms and impeding effective sterilization.
  • Because non-condensable gas (NCG) could be hiding anyplace in the chamber, not even modern sterilizers are able to find it.
  • In order to detect the NCG, sensors must be positioned inside the packs precisely where it will either be trapped or gathered.
  • This is not feasible and demonstrates the continued importance of air-removal tests for autoclave testing with today’s advanced sterilizers.
  • Autoclave‘s vacuum leak test, which only assesses the integrity of the sealed pressure vessel and associated piping, confirms that air is not being sucked (Drawn) into the sterilizer during vacuum drawdowns.


  • Bowie Dick Test Standard Recommendation:
    • It Should be as per The Association for the Advancement of Medical Instrumentation’s (AAMI) guidance ANSI/AAMI ST79 Comprehensive Guide to steam sterilization and sterility assurance in health care facilities.
  • When Bowie-Dick Tests are used or performed and its acceptance criteria?
    • Bowie Dick test should be performed to qualify sterilizer performance when first installed, anytime it is moved, and following a major repair.
    • This is qualification testing and needs three (3) successive test cycles with passing results.
    • Bowie-Dick Tests are also utilised every day the sterilizer is in use, and normal monitoring only calls for one cycle of passing tests.
    • Test process is the similar for both qualification and routine testing.

Procedure for Bowie-Dick test:

  • Step 1:
    • Do a warm-up cycle.
    • If this crucial step is skipped, the sterilizer won’t heat up properly, which could lead to falsely failing the Bowie-Dick Test.
    • The most often stage to be skipped, it causes unneeded downtime.
  • Step 2:
    • Place the Bowie-Dick Test Pack properly.
    • It must be located on the bottom rack of the sterilizer, or sterilizer cart, straight over the chamber drain.
    • Any remaining air in the chamber will inevitably move to the test pack since the vacuum is pulled from the drain.
  • Step 3:
    • Confirm the chamber is empty (Vacant). Only the sterilizer cart (on medium and floor loader sterilizers) should be present for a correct test.
    • If the cart is not included, the result could be superheated steam and a failed test.
  • Step 4:
    • Run the test cycle.
    • ANSI/AAMI ST79 does not deliver exact guidance on test cycle parameters.
    • However, they specify that the programmed exposure time should be between 3.5 min. and 4 min.
    • Follow the sterilizer and Bowie-Dick Test pack’s instructions.
  • Step 5:
    • Open the test pack and understand results.

Result and Conclusion of Bowie-Dick Test:

Bowie-Dick test
  • Check the sheet to determine if the color has moved from the center to the edges consistently and at the same intensity.
  • If the test is unsuccessful, one or more of the following factors may indicate that the sterilization system is ineffective:
  • Poor-quality steam produced by the sterilization machine.
  • Failure to make a vacuum with air being present.
  • A leak during air removal (initial vacuum phase).


  • If the test is unsuccessful, the Bowie and Dick test is performed again; if this test is successful, a third confirmatory test is conducted; if this test is also successful, sterilization can start.
  • If the second test proved unsuccessful, the autoclave must be promptly pulled out of operation.
  • If your sterilization system is ineffective, further investigation will be needed to determine the cause and find a solution because the Bowie & Dick test does not provide information regarding failure causes.

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