Sterilization Process is 21% of the scored CRCST exam. Answer 10 exam style questions on Bowie-Dick and biological indicator testing and see exactly which concepts would cost you points on test day.
Start the 10 questions →A supervisor asks a new technician what the daily Bowie-Dick test actually proves. Which answer is correct?
These questions cover bowie-Dick purpose, bowie-Dick timing, bowie-Dick applicability, bowie-Dick setup and bowie-Dick failure. Each one shows the correct answer and why every other option is wrong, so a miss tells you exactly what to review before the CRCST.
Prefer to read first? Every question from the practice set above, with the correct answer and why each wrong option is wrong.
Answer: B. The Bowie-Dick test is a Type 2 chemical indicator test that checks the air removal performance of a dynamic air removal sterilizer. It detects air leaks, inadequate air removal and noncondensable gases. It does not prove that any load is sterile.
Why not A: No chemical indicator proves sterility, and the Bowie-Dick test is run in an empty chamber with no load.
Why not C: Temperature and time are verified by the physical monitors, not by the Bowie-Dick test.
Why not D: The test does not analyze the steam for chemical contaminants.
Exam tactic: Bowie-Dick asks one question: did the air get out?
Answer: D. The Bowie-Dick test is run each day the sterilizer is used, in a preheated empty chamber, before the first processed load. A warm up cycle is run first because a cold chamber can produce a false failure. Only after a passing test are loads processed.
Why not A: Testing a cold chamber before warm up can give a false failure.
Why not B: The test is run in an empty chamber; adding a load changes the challenge and invalidates it.
Why not C: The purpose is to confirm air removal before patient loads are processed, not after.
Exam tactic: Warm up, Bowie-Dick, then load.
Answer: A. The Bowie-Dick test checks the air removal system of dynamic air removal sterilizers, such as prevacuum units. Gravity displacement sterilizers do not have that system, so the test is not used for them. Gravity units are still monitored with physical, chemical and biological indicators.
Why not B: Slow air removal in gravity cycles is addressed by longer exposure times, not by the Bowie-Dick test.
Why not C: No air removal test replaces biological indicator monitoring in any sterilizer.
Why not D: The test is not run with loads, and it does not apply to gravity displacement units.
Exam tactic: No vacuum, no Bowie-Dick.
Answer: C. The Bowie-Dick test is designed to be run alone in an empty, preheated chamber. A load changes how air is removed and how steam reaches the test pack, so the result no longer reflects the sterilizer's air removal performance.
Why not A: The test pack is used as supplied or as built per the manufacturer; it is never placed inside a tray.
Why not B: The Bowie-Dick test is a chemical indicator test and does not require a biological indicator in the pack.
Why not D: Placing the pack high near the inlet does not fix the problem; the test is invalid because of the load.
Exam tactic: Bowie-Dick rides alone.
Answer: D. A passing Bowie-Dick sheet shows a uniform color change across the whole sheet. A lighter center means air remained in the pack and steam did not penetrate evenly. The sterilizer must not be used for loads, and the supervisor and service are notified per policy.
Why not A: Any nonuniform change, especially a lighter center, is a failure even when most of the sheet changed.
Why not B: Physical monitors do not override a failed air removal test.
Why not C: A longer time does not create a pale center; uneven color shows air was trapped.
Exam tactic: Pale center equals trapped air equals fail.
Answer: C. Bacterial spores are among the most resistant forms of life to sterilization. A biological indicator with a known population of resistant spores provides a severe challenge. If those spores are killed, the process was lethal enough to destroy less resistant microorganisms.
Why not A: Biological indicators require incubation to show whether any spores survived; they do not simply change color on kill.
Why not B: Cost is not the reason; resistance is.
Why not D: The test spores are chosen for resistance, not because they commonly cause infections.
Exam tactic: Kill the toughest, and the rest are dead too.
Answer: C. Routine biological monitoring of steam sterilizers is performed at least weekly and preferably daily, in a process challenge device. Loads containing implants are monitored every time in addition to this routine schedule.
Why not A: Testing after repair is qualification testing; routine monitoring is still needed every week.
Why not B: Monthly testing is too infrequent and leaves failures undetected for weeks.
Why not D: Load contents do not decide routine BI testing, except that every implant load needs a BI.
Exam tactic: BI: weekly at minimum, daily is best.
Answer: A. The control is an unprocessed BI from the same lot as the test BI, incubated each day a test BI is run. It must show growth, proving the spores were viable and the incubator and media work. Without a valid positive control, a negative test result means nothing.
Why not B: A processed BI is a test BI, not a control, and yesterday's result belongs to yesterday.
Why not C: The control must come from the same lot, because viability can vary between lots.
Why not D: A processed BI from another sterilizer is another test, not a control.
Exam tactic: Control: same lot, never sterilized, must grow.
Answer: D. A negative test BI with a positive control is the expected and acceptable result. The control proves the spores were alive and the incubation worked, and the negative test shows the cycle killed the spores in the PCD.
Why not A: The control is supposed to grow and the test is supposed to show no growth; they should not match.
Why not B: Growth in the control is required; it is what makes the test valid.
Why not C: Both results are clear and the test is valid, so no reincubation is needed.
Exam tactic: Test negative, control positive: you are good.
Answer: B. Every load containing an implant is monitored with a PCD that holds a biological indicator, along with a Type 5 integrating indicator. Implants remain in the body, so the highest level of assurance is required for those loads.
Why not A: Textile packs do not require a BI in every load; routine BI schedules cover them.
Why not C: Peel pouches do not trigger BI monitoring of every load.
Why not D: Time of day does not determine BI monitoring.
Exam tactic: Implant in the load means BI in the load.
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