22 Quality Assurance & Monitoring Practice Questions & Answers

1. 1. A steam load has finished. Every external and internal chemical indicator changed correctly, but the cycle printout shows the chamber temperature dropped below the required exposure temperature for part of the exposure phase. What should the technician do?

   • A.Release the load, because the chemical indicators confirm the packages were sterilized
   • B.Release the non-implant packages and quarantine only the implants until the next weekly biological indicator is read
   • C.Do not release the load: report the cycle failure, reprocess the items, and document the corrective action✓ Answer
   • D.Release the load and note the temperature variance in the quality log for the next department meeting

   Release requires that the physical (mechanical), chemical and biological monitors all be acceptable. A chemical indicator only shows that its location was exposed to certain sterilant conditions; it cannot demonstrate that the required time-temperature-pressure parameters were actually achieved, and it never overrides an out-of-range physical monitor. A cycle that did not meet its parameters is a process failure, so the items are reprocessed and the failure and corrective action are documented.

   Source: ANSI/AAMI ST79, sterilization process monitoring (physical, chemical and biological monitors must all be acceptable before release); CDC/HICPAC Guideline for Disinfection and Sterilization, Sterilization MonitoringReport a problem with this question

2. 2. A wrapped tray arrives in the operating room and the indicator tape on the outside has changed color. What has that external Type 1 process indicator established?

   • A.That the contents of the package are sterile and safe to use
   • B.That air removal from the chamber was adequate during the cycle
   • C.Only that the package was exposed to a sterilization process, distinguishing it from an unprocessed package✓ Answer
   • D.That every critical variable of the cycle was met inside the pack

   A Type 1 process indicator is designed only to distinguish processed from unprocessed items. It reacts to one or more conditions at the outside surface of the package, so it says nothing about conditions inside the pack, about whether all critical variables were met, or about lethality. Sterility is inferred from the whole process — physical monitors, internal chemical indicators and biological monitoring — not from any single indicator.

   Source: ISO 11140-1, Type 1 process indicators; ANSI/AAMI ST79, use of chemical indicatorsReport a problem with this question

3. 3. A technician is assembling a multi-level orthopedic tray. Where should the internal chemical indicator be placed?

   • A.On the outside of the wrapper, next to the indicator tape
   • B.In whichever tray in the load is largest, since one indicator per load is sufficient
   • C.Inside the tray, in the area considered most challenging for the sterilant to reach, typically the center of the set✓ Answer
   • D.Only in the top corner of the tray so it is the first thing the scrub person sees

   An internal chemical indicator belongs in every package, tray and rigid container, positioned where sterilant penetration is most difficult — usually the center of the set — because an indicator placed in an easy location would pass even if the hardest-to-reach instruments were never contacted. For rigid containers the container manufacturer's written instructions for use specify the indicator locations.

   Source: ANSI/AAMI ST79, internal chemical indicator placement in every package, tray and rigid container; container manufacturer's IFUReport a problem with this question

4. 4. A new employee proposes replacing all Type 5 integrating indicators with Type 6 emulating indicators "because a higher number means a higher grade of indicator." What is the best response?

   • A.Type 6 indicators may only be used on the outside of packages, so they would replace the indicator tape
   • B.Type 6 indicators can be substituted for biological indicators when releasing implants
   • C.The types describe intended use, not quality; a Type 6 is validated for one specific cycle's parameters and is only valid in that cycle✓ Answer
   • D.He is right: the indicator types are a quality ranking, so a Type 6 always gives more assurance than a Type 5

   The ISO 11140-1 types are categories of intended use and performance, not a quality ladder. A Type 6 emulating indicator is labeled and validated for the exact parameters of one specific cycle, so using it in a different cycle makes the result meaningless; a Type 5 integrating indicator responds to all critical variables with performance correlated to a stated biological indicator. Neither replaces a biological indicator, and a Type 6 cannot be the basis for early release of an implant.

   Source: ISO 11140-1, chemical indicator types 1-6 as intended-use categories; ANSI/AAMI ST79, indicator selection and early release of implantsReport a problem with this question

5. 5. After a cycle ends, a new technician asks who is responsible for deciding that a routine (non-implant) load may be released for use. What is correct?

   • A.Only the department manager may read printouts, so no load leaves until the manager signs each one
   • B.The trained technician operating the sterilizer reviews the printout against the required parameters, initials it, and verifies package integrity, dryness and indicator results✓ Answer
   • C.Release is automatic: if the sterilizer door opens without an alarm, the load is considered released
   • D.The circulating nurse in the operating room releases the load when the case cart is delivered

   The person who operates the sterilizer reviews and interprets the physical monitoring record and initials or signs it, because that record becomes part of the legal load record tied to the load control number and shows who verified the cycle. Release also requires acceptable external and internal chemical indicator results and intact, dry packaging; the internal indicator is finally checked by the user at the point of use.

   Source: ANSI/AAMI ST79, review and interpretation of physical monitors and load release; HSPA CRCST Content Outline Sec. 4 sub-domain VII (post-sterilization)Report a problem with this question

6. 6. Why is a biological indicator described as the only monitor that gives direct evidence that a sterilization cycle achieved lethality?

   • A.Because it measures chamber temperature and pressure more precisely than the sterilizer gauges
   • B.Because it contains a known population of highly resistant bacterial spores, so killing that challenge population demonstrates the process was lethal✓ Answer
   • C.Because it is placed on the outside of the package, where the sterilant reaches first
   • D.Because it changes color in response to steam, ethylene oxide and hydrogen peroxide at the same time

   A biological indicator carries a standardized population of spores chosen for their resistance to the specific sterilization method. If that population is inactivated, the cycle delivered enough lethality to kill organisms far more resistant than ordinary contaminants. Physical monitors only show parameters were reached and chemical indicators only show exposure; neither measures microbial kill.

   Source: ANSI/AAMI ST79 and ISO 11138, biological indicators for sterilization processesReport a problem with this question

7. 7. Which spore-forming organism is used in a biological indicator to challenge a steam sterilization cycle, and why?

   • A.Staphylococcus aureus, because it survives on dry surfaces for long periods
   • B.Bacillus atrophaeus, because its spores are highly resistant to moist heat
   • C.Geobacillus stearothermophilus, because its spores are highly resistant to moist heat✓ Answer
   • D.Clostridioides difficile, because it is the most common healthcare-associated pathogen

   Geobacillus stearothermophilus spores are the recognized challenge for steam because they are far more resistant to moist heat than the microorganisms found on used instruments; the same organism is used for vaporized hydrogen peroxide and ozone processes. The organism is selected to be harder to kill than anything the process will realistically encounter, so a negative result gives a wide margin of assurance.

   Source: ISO 11138-3 (biological indicators for moist heat); ANSI/AAMI ST79; CDC/HICPAC Guideline, Sterilization MonitoringReport a problem with this question

8. 8. A department runs both an ethylene oxide sterilizer and a dry-heat oven. Which biological indicator organism challenges those two processes?

   • A.Escherichia coli, because it is easy to culture and inexpensive
   • B.Mycobacterium terrae, the standard challenge organism for all low-temperature processes
   • C.Geobacillus stearothermophilus, which is used for every sterilization method
   • D.Bacillus atrophaeus, whose spores are the recognized challenge for ethylene oxide and dry heat✓ Answer

   The challenge organism is matched to the killing mechanism of the process. Bacillus atrophaeus spores are especially resistant to ethylene oxide gas and to dry heat, while Geobacillus stearothermophilus is used for moist heat, vaporized hydrogen peroxide and ozone. Using the wrong organism would not present a meaningful challenge and the negative result would be meaningless. Ethylene oxide loads are monitored with a biological indicator in every load.

   Source: ISO 11138-2 (ethylene oxide) and ISO 11138-4 (dry heat); ANSI/AAMI ST79; CDC/HICPAC Guideline, Sterilization MonitoringReport a problem with this question

9. 9. A processed biological indicator shows no growth, but the unprocessed control biological indicator incubated alongside it also shows no growth. How should the technician interpret this?

   • A.The sterilizer must be taken out of service and every load recalled back to the last negative biological indicator
   • B.The control should simply be re-incubated for a second full incubation period and then recorded as passing
   • C.The test is invalid and must be repeated with a new test and control indicator from the same lot✓ Answer
   • D.The load is confirmed sterile, since neither indicator grew

   The control is an unprocessed biological indicator from the same lot number, incubated each day a processed indicator is run. It must show growth to prove the spores were viable and the incubator was working; if the control does not grow, the negative result on the processed indicator proves nothing and the whole test is invalid. This is a test failure, not a sterilizer failure, so it is repeated and documented rather than triggering a recall.

   Source: ANSI/AAMI ST79, biological indicator control requirements; ISO 11138 (BI performance and controls)Report a problem with this question

10. 10. What is the purpose of placing the biological indicator inside a process challenge device (PCD) rather than loose on a shelf?

    • A.It provides a convenient place to attach the load control label
    • B.It reduces the challenge to the indicator so that results are more consistent from load to load
    • C.It presents a challenge to the process equal to or greater than the most difficult item routinely processed, so a pass implies easier items were also reached✓ Answer
    • D.It measures the residual soil left on instruments after cleaning

    A PCD deliberately makes it harder for the sterilant to reach the indicator than any routine item in the load. Because the worst case passed, the technician can infer the rest of the load was at least as well exposed. An indicator sitting unprotected on a shelf would be exposed more easily than the packages, so a pass would tell nothing about the packaged instruments.

    Source: ANSI/AAMI ST79, process challenge devices for routine sterilizer efficacy monitoringReport a problem with this question

11. 11. Where should the biological indicator PCD be placed in a loaded steam sterilizer chamber?

    • A.On the top shelf at the back, where steam collects first
    • B.Outside the chamber, attached to the printout so it is not lost
    • C.Anywhere in the chamber, because conditions inside a sterilizer are uniform
    • D.On the bottom shelf, in the front, over or near the drain — the area hardest for air removal and steam contact✓ Answer

    Air is heavier than steam and settles in the lower front of the chamber near the drain, making that the coldest and most challenging location. Testing the worst spot means a negative result covers the rest of the chamber. Placing the PCD in an easy location would produce a pass that does not represent the load.

    Source: ANSI/AAMI ST79, placement of the process challenge device in the steam sterilizer chamberReport a problem with this question

12. 12. A load being assembled contains an orthopedic implant set. What monitoring does that load require?

    • A.A Bowie-Dick test pack placed alongside the implants
    • B.An external chemical indicator only; internal indicators are optional for implant sets
    • C.A biological indicator in a process challenge device in that load, with the load quarantined until the result is read as negative✓ Answer
    • D.Nothing beyond the department's routine periodic biological monitoring schedule

    Every load containing implants is monitored with a biological indicator in a PCD, because an implant is placed in a sterile body site where an infection is severe and difficult to treat, and the item cannot be re-examined once implanted. The load is held until the biological indicator result is known and negative; chemical indicators alone are not an acceptable basis for routine implant release.

    Source: ANSI/AAMI ST79, monitoring and quarantine of loads containing implants; CDC/HICPAC Guideline, Sterilization MonitoringReport a problem with this question

13. 13. A technician has been running a Bowie-Dick test each morning in a gravity-displacement steam sterilizer. What should a supervisor explain?

    • A.The practice is correct, since every steam sterilizer requires a daily Bowie-Dick test
    • B.A Bowie-Dick test can replace the biological indicator on any steam sterilizer
    • C.The test evaluates air removal and steam penetration and therefore applies to dynamic-air-removal (prevacuum) sterilizers, not to gravity-displacement sterilizers✓ Answer
    • D.The test is valid on a gravity sterilizer only when the chamber is fully loaded

    The Bowie-Dick (air-removal/DART) test detects air leaks and non-condensable gases that would prevent steam from penetrating a pack in a vacuum-assisted cycle. A gravity-displacement sterilizer has no vacuum phase, so the test does not apply to it. The test evaluates air removal only — it is not a sterility test and never substitutes for biological monitoring.

    Source: ANSI/AAMI ST79, Bowie-Dick (air-removal) testing of dynamic-air-removal steam sterilizersReport a problem with this question

14. 14. Which description matches the correct way to perform a daily Bowie-Dick test on a prevacuum steam sterilizer?

    • A.Extend the exposure to at least 10 minutes so the pack receives a thorough challenge
    • B.Run it each day of use as the first cycle after a warm-up cycle, in an otherwise empty chamber, with the pack on the bottom shelf over or near the drain✓ Answer
    • C.Run it at the end of the day inside a full load, with the pack on the top shelf
    • D.Run it once a week with the day's first instrument load inside the chamber

    The chamber must be empty so nothing but the test pack affects air removal, and the warm-up cycle prevents a false failure caused by a cold chamber. The bottom shelf over the drain is where residual air collects. Exposure time follows the test manufacturer's instructions and is kept short (not exceeding about four minutes), because an over-long exposure can drive steam into the pack and produce a false pass.

    Source: ANSI/AAMI ST79, Bowie-Dick test procedure (empty chamber, first cycle after warm-up, bottom shelf near the drain); test-pack manufacturer's IFUReport a problem with this question

15. 15. The morning Bowie-Dick test on a prevacuum sterilizer shows a non-uniform, failed result. What is the correct next step?

    • A.Recall every item processed in that sterilizer back to the last negative biological indicator
    • B.Do not process routine loads; repeat the test as directed, and if it fails again remove the sterilizer from service for repair and requalification✓ Answer
    • C.Switch the sterilizer to gravity cycles and keep using it for the day
    • D.Continue processing loads, since a Bowie-Dick test is not a sterility test

    A failed air-removal test means air, a leak or non-condensable gases may prevent steam from reaching the center of packs, so packs processed in that condition cannot be assumed to have been exposed. The test is repeated to rule out a procedural cause such as a missing warm-up cycle or a misplaced pack; persistent failure means a mechanical problem and the sterilizer stays out of service until repaired and requalified.

    Source: ANSI/AAMI ST79, response to a failed Bowie-Dick (air-removal) test; qualification testing after repairReport a problem with this question

16. 16. An operating room calls for an implant tray that finished its cycle 20 minutes ago. The biological indicator is still incubating and no emergency has been declared or documented. What should the technician do?

    • A.Release it now and reprocess the implant after the case if the biological indicator turns positive
    • B.Release it, because the initialed cycle printout is sufficient evidence for any load
    • C.Release it, because the internal Type 5 integrating indicator is an acceptable basis for routine implant release
    • D.Keep the implant quarantined until the biological indicator is read as negative, and communicate the status to the operating room✓ Answer

    Implant loads are quarantined until the biological indicator result is known and negative, because the biological indicator is the only monitor that demonstrates the cycle killed a resistant spore challenge and an implanted device cannot be retrieved or re-examined. Releasing on chemical indicators alone is permitted only as a documented emergency, which does not exist here; the correct action is to hold the tray and tell the operating room.

    Source: ANSI/AAMI ST79, quarantine of implant loads pending biological indicator results; CDC/HICPAC Guideline, Sterilization MonitoringReport a problem with this question

17. 17. A true documented emergency arises: a patient is open on the table and the only available implant is in a load whose biological indicator is still incubating. Which statement describes acceptable practice?

    • A.Release it on the basis of the external Type 1 process indicator and discard the biological indicator
    • B.Release it on the basis of a Type 6 emulating indicator; the biological indicator need not be incubated
    • C.Release it early only on an acceptable Type 5 integrating indicator inside the implant PCD, while the biological indicator continues to incubate, with the result documented and the release traceable to the patient✓ Answer
    • D.Reprocess the implant with immediate-use steam sterilization, which is the routine method for implants

    Early release is an exception, not an option of convenience. It rests on a Type 5 integrating indicator inside the implant process challenge device because that indicator responds to all critical variables and its performance is correlated to a stated biological indicator. The biological indicator must still be incubated and the result documented so that, if it is positive, the patient who received the implant can be identified. The emergency and the release must be documented and reviewed.

    Source: ANSI/AAMI ST79, emergency early release of implants based on a Type 5 integrating indicator in the implant PCD, with BI incubated and documentedReport a problem with this question

18. 18. A biological indicator from this morning's steam load is positive. The sterilizer's previous negative biological indicator was three days ago, and 11 loads have run since. Which items must be treated as non-sterile?

    • A.Every item in sterile storage, regardless of which sterilizer processed it
    • B.Only the implants from that load; non-implant items are always exempt from recall
    • C.All items processed in that sterilizer since the last negative biological indicator, which must be retrieved and reprocessed✓ Answer
    • D.Only the items in the load that contained the positive biological indicator

    A positive biological indicator only tells you when the failure was detected, not when it began, so every load run in that sterilizer back to the last negative biological indicator is suspect and is recalled and reprocessed. The load control numbers on each package are what make that retrieval possible. Implants are always quarantined or recalled; the recall boundary is defined by the last negative result, not by the failed load.

    Source: CDC/HICPAC Guideline for Disinfection and Sterilization, sterilization failure and recall; ANSI/AAMI ST79, recall to the last negative biological indicatorReport a problem with this question

19. 19. A biological indicator is read as positive. Which sequence of actions is correct?

    • A.Keep using the sterilizer for non-implant loads while the investigation is under way, since only implants are at risk
    • B.Take the sterilizer out of service, notify the supervisor and infection prevention/risk management, use the load control numbers to identify affected loads, retrieve and reprocess them, investigate the cause, and document everything✓ Answer
    • C.Discard the failed indicator and the cycle printouts so the records are not confusing, then notify maintenance
    • D.Rerun the cycle; if the second biological indicator is negative, release the original load retroactively and make no report

    A positive biological indicator is a process failure with potential patient impact, so the sterilizer is removed from service and the people who manage patient risk — the supervisor, infection prevention and risk management — are notified. Load control numbers make the affected packages traceable so they can be retrieved. Records, including the failed indicator result and the printouts, are legal documents and must be retained, never discarded; the cause is investigated and the corrective action documented.

    Source: CDC/HICPAC Guideline for Disinfection and Sterilization, suggested protocol for a positive spore test; ANSI/AAMI ST79, process failures, recall and documentationReport a problem with this question

20. 20. Thirty minutes after a steam cycle, a technician finds a tray whose outer wrapper is damp, although the instruments inside feel dry. What is the correct action?

    • A.Treat the package as contaminated, remove it from use, reprocess it with new packaging, and investigate the cause of the wet pack✓ Answer
    • B.Wipe the outside dry and send it out, since moisture on the outside does not affect the contents
    • C.Place the tray in a warming cabinet until the wrapper dries, then release it
    • D.Apply a second wrapper over the damp one and label it for immediate use

    Moisture in or on packaging creates a wicking path that lets microorganisms travel from the outside surface through the barrier to the contents, so a wet or damp package is considered contaminated regardless of where the moisture is. It is reprocessed with new packaging and the cause — overloading, poor load configuration, insufficient dry time, or cooling in a draft or on a cold solid surface — is investigated and documented so it does not recur.

    Source: ANSI/AAMI ST79, wet packs and load cooling/sterility maintenanceReport a problem with this question

21. 21. What information makes up the load control (lot) identifier applied to each package, and why is it required?

    • A.The count sheet number and the wrapper lot number, so packaging defects can be tracked
    • B.The patient's name, the surgeon and the date of the procedure, so charges can be posted
    • C.The sterilizer identification, the cycle or load number for that day, and the date of sterilization — so any item can be traced back to its load for recall, patient traceability and record retention✓ Answer
    • D.The technician's badge number and the shelf-life expiration date only, so stock can be rotated

    The load control identifier links a package to a specific sterilizer, a specific cycle and a specific date. Without those three elements a facility could not determine which packages were affected by a failed cycle, could not trace a device to the patient it was used on, and could not support the sterilization record as a retained legal document. The load record itself also lists contents, cycle parameters, operator and monitoring results.

    Source: ANSI/AAMI ST79, load control/lot identification and load documentation; HSPA CRCST Content Outline Sec. 4 sub-domain IX (documentation of load contents)Report a problem with this question

22. 22. A steam sterilizer has just undergone a major repair to its vacuum pump. What testing is required before it returns to routine use?

    • A.Run one biological indicator in the next routine load; if it is negative, resume normal processing
    • B.Run a single Bowie-Dick test; biological indicators are not needed after a mechanical repair
    • C.Run three consecutive cycles with a biological indicator PCD in an empty chamber, all negative — plus three consecutive Bowie-Dick tests for a dynamic-air-removal sterilizer — keeping the sterilizer out of service until all results are acceptable and documented✓ Answer
    • D.No testing is needed if the service technician provides a certificate of repair

    Qualification (requalification) testing is required after installation, relocation, major repair, malfunction, a sterilization process failure, or a significant utility interruption. Three consecutive negative results in an empty chamber demonstrate the machine performs reliably and not by chance, and the empty chamber isolates sterilizer performance from load variables. A dynamic-air-removal sterilizer also needs consecutive air-removal tests because vacuum performance was the thing repaired. The sterilizer stays out of service until every result is acceptable and documented.

    Source: ANSI/AAMI ST79, sterilizer qualification/requalification testing after installation, relocation or major repairReport a problem with this question

Practice questions based on the HSPA CRCST Certification Exam Content Outline, ANSI/AAMI ST79 sterility-assurance practice, and CDC/HICPAC disinfection and sterilization guidance. CRCST is a mark of the Healthcare Sterile Processing Association; this site is not affiliated with or endorsed by HSPA. Always follow the device manufacturer's written instructions for use, your facility's policies, and the current edition of the applicable standards. About the CRCST exam →