CRCST practice test: Sterilization Process

10 questions · about 12 minutes. Pick an answer to see whether you’re right and why.

1. Question 1 of 10According to CDC, what is the minimum exposure time for wrapped instruments in a gravity displacement steam sterilizer at 250°F (121°C)?

   A.4 minutesB.10 minutesC.15 minutesD.30 minutes
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   Answer: D. 30 minutes

   CDC Table 7 lists 30 minutes at 121°C for wrapped instruments in a gravity displacement sterilizer (15 minutes at 132°C), with 15–30 minutes of drying.

2. Question 2 of 10How often does CDC say an air-removal (Bowie-Dick) test must be run in a dynamic-air-removal steam sterilizer?

   A.Weekly, with a full loadB.Monthly, after maintenance onlyC.Daily, in an empty chamberD.Only when a biological indicator fails
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   Answer: C. Daily, in an empty chamber

   CDC: an air-removal test (Bowie-Dick test) must be performed daily in an empty dynamic-air-removal sterilizer. It checks that air is removed, which a gravity sterilizer does not do with a vacuum.

3. Question 3 of 10According to CDC, how often should steam sterilizers be monitored with biological indicators, at minimum?

   A.Once a yearB.At least weekly, and with every load that contains implantable itemsC.Only after repairsD.Only for loads processed at night
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   Answer: B. At least weekly, and with every load that contains implantable items

   CDC: monitor at least weekly with spores; daily use allows earlier discovery of malfunctions in busy sterilizers; and each load containing implantable objects should be monitored.

4. Question 4 of 10A biological indicator from a steam load is positive. How does CDC’s guideline treat this?

   A.As a possible sterilizer malfunction: items processed since the last negative BI are considered nonsterile and retrieved if possibleB.As a normal result that needs no actionC.As a problem only with the indicator, so the load is releasedD.As a reason to re-run the BI and release the load if the second one is negative
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   Answer: A. As a possible sterilizer malfunction: items processed since the last negative BI are considered nonsterile and retrieved if possible

   CDC’s conservative approach treats any positive spore test as a sterilizer malfunction. Items processed from the cycle with the last negative BI onward are considered nonsterile, retrieved if possible and reprocessed.

5. Question 5 of 10Which packaging should not be used in a hydrogen peroxide gas plasma sterilizer?

   A.Tyvek-plastic pouchesB.Polypropylene wrapC.Rigid containers validated for that sterilizerD.Cellulose-based materials such as paper-plastic pouches and linen
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   Answer: D. Cellulose-based materials such as paper-plastic pouches and linen

   Cellulose absorbs hydrogen peroxide and can cause the cycle to abort or fail. Use packaging the sterilizer manufacturer has validated for the cycle.

6. Question 6 of 10A wrapped tray comes out of a steam cycle with visible moisture on the wrap. What should be done?

   A.Let it dry on the shelf, then release itB.Wipe it dry and release itC.Treat it as contaminated, do not release it, reprocess it and look for the causeD.Release it if the external indicator changed
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   Answer: C. Treat it as contaminated, do not release it, reprocess it and look for the cause

   Moisture can wick microorganisms through the packaging, so a wet pack is considered contaminated. Common causes include overloading, heavy sets, poor steam quality and improper loading.

7. Question 7 of 10How should basins and other items that can hold water be positioned in a steam sterilizer load?

   A.Upright, so they can collect steamB.On their sides or tilted so condensate drains awayC.Upside down and stacked tightlyD.Nested together with towels between them
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   Answer: B. On their sides or tilted so condensate drains away

   Items that hold water trap condensate and air, which leads to wet packs and poor steam contact. Tilting them lets condensate drain and steam circulate.

8. Question 8 of 10Which of these is not one of the four parameters of steam sterilization named by CDC?

   A.Gas concentrationB.SteamC.PressureD.Time
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   Answer: A. Gas concentration

   CDC names four parameters of steam sterilization: steam, pressure, temperature and time. Gas concentration is a parameter of low-temperature methods such as ethylene oxide.

9. Question 9 of 10A steam load has just been removed from the chamber. What should happen before the packs are handled?

   A.Move them straight onto cold metal shelvesB.Place them under a fan to cool fasterC.Stack them in a closed bin while warmD.Leave them on the loading cart to cool in a low-traffic area away from air vents
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   Answer: D. Leave them on the loading cart to cool in a low-traffic area away from air vents

   Warm packs can draw in moisture and contamination if handled or placed on cold surfaces. Letting the load cool undisturbed protects the sterile barrier.

10. Question 10 of 10According to CDC, which items should not undergo flash (immediate-use) steam sterilization?

    A.Unwrapped stainless steel instruments needed urgentlyB.Nonporous itemsC.Implantable devicesD.Items dropped during a procedure that are needed right away
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    Answer: C. Implantable devices

    CDC: flash sterilization should not be used for implanted devices, and not for convenience or as a substitute for enough instrument sets.