22 Infection Prevention Practice Questions & Answers

1. 1. A contaminated instrument that is reused without reprocessing can carry organisms from one patient to the next. In terms of the chain of infection, what does cleaning and sterilizing that instrument accomplish?

   • A.It removes the susceptible host from the chain, since a device that has been processed can no longer make a patient vulnerable to infection.
   • B.It removes the infectious agent from the department, since no reservoir of organisms is left once every instrument set has been processed.
   • C.It closes the portal of exit, since organisms can no longer leave the first patient's wound once the instrument used there has been processed.
   • D.It interrupts the mode of transmission, since the instrument is the vehicle that would otherwise carry organisms to the next patient.✓ Answer

   Reprocessing acts on the link where the device itself is the vehicle of indirect-contact transmission. The agent still exists, reservoirs still exist and patients remain susceptible, so the chain is broken at transmission rather than eliminated.

   Source: CDC Guideline for Disinfection and Sterilization in Healthcare Facilities (2008), rationale for reprocessing reusable patient-care devicesReport a problem with this question

2. 2. A technician has worn gloves for a series of tasks in the decontamination area, and the gloves show no visible tears or soil. When is hand hygiene required?

   • A.After the gloves become visibly soiled or torn, since gloves that stay intact keep the hands clean through the whole series of tasks performed.
   • B.After the shift ends and before the next one begins, since washing repeatedly between glove changes damages the skin barrier of the hands.
   • C.After each glove removal and before a new pair is donned, since gloves can have unseen defects and hands are contaminated during removal.✓ Answer
   • D.After leaving the department for a break or a meal, since the hands stay covered by the gloves during every task performed in the area.

   Gloves are not a substitute for hand hygiene: they can carry unrecognized perforations, and organisms are transferred to the skin during removal. Hand hygiene is therefore performed after doffing and before donning a fresh pair.

   Source: CDC Guideline for Hand Hygiene in Health-Care Settings, indications for hand hygiene after glove removalReport a problem with this question

3. 3. A new technician asks why decontamination is a separate, enclosed room with a pass-through rather than one end of the preparation area. What is the reason?

   • A.A physical barrier lets each area keep its own sterilizer cycle records, so that load numbers are never mixed up between the two rooms.
   • B.A separate room lets soiled trays be held until staffing allows them to be cleaned, so the preparation area is never slowed down by a backlog.
   • C.A separate room keeps the noise of ultrasonic cleaners and washers away from the staff who assemble trays and work through count sheets.
   • D.A physical barrier and a single direction of flow keep aerosols, splash and soiled items from reaching instruments that have already been cleaned.✓ Answer

   Cleaning generates aerosols and splash, and soiled items and personnel are themselves contaminated. Enclosing decontamination and moving items in one direction only, from soiled to clean to sterile, prevents recontamination of processed items.

   Source: ANSI/AAMI ST79, physical separation of the decontamination area from clean work areas and unidirectional workflowReport a problem with this question

4. 4. A cart is propping open the door between decontamination and the clean corridor, and the room's pressure monitor now shows air moving out of decontamination toward the clean side. What should the technician do?

   • A.Clear the doorway so the door closes, notify the supervisor and facilities, and document the finding so that the affected period of time can be reviewed.✓ Answer
   • B.Set up a floor fan in the doorway aimed back into decontamination, which restores the intended direction of air movement until facilities can respond.
   • C.Leave the door open until the cart is unloaded, since air movement cannot contaminate instruments that are inside closed containers and covered carts.
   • D.Move the cleaning work to the far end of the room and continue, since the direction of airflow matters only while a washer door is open and steam escapes.

   Decontamination is held at a lower pressure than the areas around it so that air always moves into the soiled room and never out of it. A propped door reverses that direction, which is a facility problem to be corrected, reported and documented rather than worked around.

   Source: ANSI/AAMI ST79, decontamination area maintained at negative pressure relative to adjacent areasReport a problem with this question

5. 5. A closed transport container of soiled instruments is found in the corridor with fluid leaking from one corner onto the floor. What is the correct response?

   • A.Wearing appropriate protection, contain the leak, have the corridor cleaned and disinfected, and report the container so that it is removed from service.✓ Answer
   • B.Carry the container quickly to the decontamination sink, wipe the corridor floor dry with a paper towel, and put the container back into service afterward.
   • C.Cover the leak with an absorbent pad and finish the delivery route first, then report the container at the end of the shift when the carts are returned.
   • D.Return the container to the procedure room that sent it, so that the staff there can transfer the instruments into a second container of the same type.

   Contaminated instruments must be transported in a container that is closed and leak resistant, so a leak means containment has failed and the corridor is now contaminated. The spill is contained and decontaminated and the failed container is taken out of use.

   Source: OSHA Bloodborne Pathogens Standard, 29 CFR 1910.1030, containment of contaminated equipment during handling and transportReport a problem with this question

6. 6. A tray arrives in decontamination with loose scalpel blades and suture needles mixed in among the instruments. How should the technician proceed?

   • A.Put on a second pair of gloves and pick the sharps out by hand, since double gloving gives enough protection for the small number of sharp items involved.
   • B.Run the whole tray through the washer-disinfector first, then sort the sharps out by hand once the cycle has rendered the contents of the tray safe to handle.
   • C.Use forceps or another hands-free device to move the sharps into a sharps container, then report the point-of-use failure so the sending area can correct it.✓ Answer
   • D.Send the tray back to the procedure area unopened, since sorting sharps out of a soiled set is not a task that is ever performed in the decontamination area.

   Contaminated sharps are never manipulated with the hands, because a puncture through soiled gloves is a bloodborne pathogen exposure; a mechanical means such as forceps is used and the sharp goes straight into a sharps container. Sharps should have been removed at the point of use, so the lapse is reported.

   Source: OSHA Bloodborne Pathogens Standard, 29 CFR 1910.1030, handling of contaminated sharps without the handsReport a problem with this question

7. 7. A technician is punctured by a soiled instrument while emptying a transport container. Under the bloodborne pathogen requirements, what does this exposure incident oblige?

   • A.The injury must be reported only where the source patient is known to carry a bloodborne pathogen, since testing is otherwise neither warranted nor offered.
   • B.The injury must be reported so that a confidential medical evaluation and follow-up are offered to the technician at no cost, and so the event is recorded.✓ Answer
   • C.The injury may be managed with first aid alone where the puncture is shallow, and the technician decides afterward whether to tell the employee health office.
   • D.The injury must be reported to the infection prevention department alone, which then decides whether the technician's own physician needs to be involved at all.

   An exposure incident triggers a confidential post-exposure evaluation and follow-up made available by the employer at no cost to the worker, and the injury is documented. None of that depends on already knowing the source patient's status.

   Source: OSHA Bloodborne Pathogens Standard, 29 CFR 1910.1030, post-exposure evaluation and follow-upReport a problem with this question

8. 8. Instruments used on brain tissue in a patient with suspected Creutzfeldt-Jakob disease arrive in decontamination. How should they be handled?

   • A.Let them dry so the residue can be scraped away, then run them through the washer twice before a routine steam cycle with a lengthened exposure phase.
   • B.Soak them in a high-level disinfectant before a routine steam cycle, since that agent destroys the material a conventional cycle is unable to inactivate.
   • C.Keep them wet and segregated, and process them by the facility's prion protocol under infection prevention direction instead of on the routine pathway.✓ Answer
   • D.Process them exactly as any other neurosurgical set, since a cycle that kills bacterial spores also inactivates every other agent known to be transmissible.

   Prions are far more resistant than the organisms a routine cycle is validated against, and drying makes the residue harder still to remove. High-risk tissue therefore follows a special protocol, decided with infection prevention, rather than the normal pathway.

   Source: CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, special pathogens: Creutzfeldt-Jakob diseaseReport a problem with this question

9. 9. Sterilization processes are challenged with preparations of bacterial spores rather than with other microorganisms. What is the reason?

   • A.Spores withstand sterilizing conditions better than vegetative bacteria, fungi, viruses and mycobacteria, so killing them implies the rest were killed.✓ Answer
   • B.Spores grow faster in culture than the other organisms, so the result can be read soon enough for the load to be released during the same working day.
   • C.Spores are the organisms most often recovered from surgical instruments, so the challenge matches the contamination that is actually present in a given load.
   • D.Spores are harmless to the staff who handle the indicator, while the other organisms used in testing would need containment in a separate laboratory.

   Microorganisms fall into a descending order of resistance, and bacterial spores sit at the top of the conventional organisms. A process demonstrated to destroy a spore population has therefore also destroyed the less resistant organisms below it.

   Source: CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, descending order of resistance of microorganisms to germicidesReport a problem with this question

10. 10. A semicritical device tolerates no heat process at all, and its instructions direct liquid chemical processing. What is the minimum level of processing required, and what defines that level?

    • A.Intermediate-level disinfection, a level defined by the ability to kill mycobacteria, which is what contact with a mucous membrane is taken to require.
    • B.High-level disinfection, a level that destroys all microorganisms except large numbers of bacterial spores, on a device that has first been cleaned.✓ Answer
    • C.Sterility by liquid immersion alone, a process that leaves the device sterile and able to be stored for later use in the same way as a wrapped tray.
    • D.Low-level disinfection, a level that kills vegetative bacteria and enveloped viruses, which suffices wherever a device does not enter the bloodstream.

    Semicritical items contact mucous membranes or non-intact skin, and their floor is high-level disinfection, which is defined by activity against all microorganisms except large numbers of spores. The device must be cleaned first, since disinfection cannot act through soil.

    Source: CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, Spaulding classification and definition of high-level disinfectionReport a problem with this question

11. 11. A basin of high-level disinfectant passes the concentration test strip this morning, but the reuse period printed on the product label ran out yesterday. What should the technician do?

    • A.Continue using the solution for items that are already clean, and reserve the freshly prepared basin for devices arriving with heavier soil.
    • B.Continue using the solution until a strip fails, because the strip measures what actually matters and a passing result shows that the solution still works.
    • C.Add fresh concentrate to the basin to renew the reuse period, then record the new date and keep the solution in service until that later date arrives.
    • D.Discard the solution and prepare a fresh basin, because the reuse period and the concentration test are separate limits and whichever expires first governs.✓ Answer

    The test strip shows only that the active ingredient is still above its minimum effective concentration; it says nothing about the degradation and dilution the solution has undergone over its labeled reuse period. The two limits run in parallel and the earlier one ends the solution's life.

    Source: CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, minimum effective concentration testing and reuse life of high-level disinfectantsReport a problem with this question

12. 12. The same ultrasound transducer is used on intact skin for a bedside scan and, in a later procedure, is introduced into a sterile joint space. Under the Spaulding classification, what does this mean?

    • A.Its category is fixed by the device itself: transducers are semicritical, so high-level disinfection covers both uses wherever the probe is placed.
    • B.Its category follows the use at hand: noncritical for the skin scan and critical for the joint entry, so it must be sterilized before the joint procedure.✓ Answer
    • C.Its category is fixed as noncritical, because the transducer meets the patient only through a probe cover and disinfection of the housing is sufficient.
    • D.Its category rises by one level for the joint entry, from noncritical to semicritical, so high-level disinfection is what the joint procedure calls for.

    Spaulding categories are assigned by what the device will contact on that occasion, not by what the device is called. A probe entering a normally sterile space is a critical item for that use, and a cover does not lower the requirement.

    Source: CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, Spaulding classification by intended use; CDC guidance on ultrasound probe reprocessingReport a problem with this question

13. 13. A transesophageal echocardiography probe contacts the mucous membrane of the esophagus and does not enter sterile tissue. What does the Spaulding classification require for it?

    • A.Semicritical handling, so the probe is cleaned and then at minimum high-level disinfected, with sterilization used where the device tolerates it.✓ Answer
    • B.Noncritical handling, so the probe is cleaned and wiped with a low-level disinfectant, because the esophageal lining counts as an intact body surface.
    • C.Critical handling, so the probe is sterilized before every use, because any device passed inside the body is treated as entering sterile tissue.
    • D.Semicritical handling, so a thorough cleaning with an enzymatic detergent suffices, because cleaning removes the organisms a disinfectant would kill.

    Contact with a mucous membrane places a device in the semicritical category, whose minimum is high-level disinfection after cleaning. Cleaning alone is not disinfection, and mucous membranes are not treated as intact skin.

    Source: CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, semicritical items contacting mucous membranesReport a problem with this question

14. 14. The pump of a sequential compression device and its patient sleeves are returned to the department from a nursing unit. What is the correct handling under the Spaulding classification?

    • A.Discard the single-use sleeves, then send the pump for high-level disinfection, because it was in continuous contact with the patient's skin for several hours.
    • B.Clean the sleeves and the pump together in the washer-disinfector, then return both to circulation once the thermal phase of the cycle has finished.
    • C.Wipe the pump housing and the sleeves with a disinfectant, then bag them together so that the unit is issued as a complete set to the next patient.
    • D.Discard the single-use sleeves, then clean the pump housing and disinfect it, keeping the surface wet for the contact period stated on the product label.✓ Answer

    A pump housing contacts intact skin at most, which makes it noncritical: cleaning followed by disinfection at the product's labeled contact time. The sleeves are single-use and are discarded rather than reprocessed for another patient.

    Source: CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, noncritical patient-care items and use of germicides per label contact timeReport a problem with this question

15. 15. A rigid arthroscope is introduced into the knee joint during surgery. Under the Spaulding classification, how must it be reprocessed?

    • A.As a semicritical device, it is cleaned and high-level disinfected, because endoscopes as a group contact mucous membranes rather than deep tissue.
    • B.As a critical device, it is cleaned and then sterilized, because it enters a joint space that is sterile and would receive any organism left on it.✓ Answer
    • C.As a critical device, it is cleaned and high-level disinfected, because the optics of a rigid endoscope cannot survive any method of sterilization.
    • D.As a semicritical device, it is sterilized when time allows and otherwise disinfected, because a joint is not a part of the vascular system of the body.

    A device that enters a normally sterile body space is critical and must be sterilized, whatever family of instruments it belongs to. Calling an item an endoscope does not move it into the semicritical group.

    Source: CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, critical items entering sterile tissue or the vascular systemReport a problem with this question

16. 16. Which statement describes a recognized limitation of the Spaulding classification?

    • A.It applies only to reusable devices and offers no guidance at all for an item the manufacturer has labeled for use on a single patient.
    • B.It sets the level by the department that owns the device, so an item shared between two services ends up with two conflicting requirements.
    • C.It assigns the level by the tissue contacted and does not resolve prions, biofilm, or channels too narrow for cleaning and sterilant contact.✓ Answer
    • D.It ranks organisms by resistance but gives no method for deciding whether a device touches sterile tissue, mucous membranes or intact skin.

    The scheme predicts risk from the tissue a device contacts, which works well for open instruments. It does not account for agents outside the ordinary resistance order, for organisms sheltered in biofilm, or for lumens that a process cannot reliably reach.

    Source: CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, limitations of the Spaulding schemeReport a problem with this question

17. 17. Every item arriving in decontamination is handled as contaminated, whatever the patient's diagnosis happens to be. What is the basis for this practice?

    • A.Transmission-based precautions require the highest level of protection on every item until the sending unit has confirmed the patient's infectious status.
    • B.Standard precautions treat blood and body fluid from every patient as potentially infectious, because a patient's infectious status is often unknown.✓ Answer
    • C.Items are assumed contaminated because a sterilizer cannot be validated unless every load presents a comparable and predictable level of bioburden.
    • D.Items are assumed contaminated because staff cannot be expected to read the patient labels attached to each container during a busy working shift.

    Standard precautions apply to all patients at all times because infection is frequently undiagnosed at the moment care is given. Sorting instruments by known diagnosis would leave staff unprotected against the cases nobody has identified yet.

    Source: CDC Guideline for Isolation Precautions, standard precautions applied to all patients regardless of diagnosisReport a problem with this question

18. 18. Why can residual organic soil on a device defeat a high-level disinfection or sterilization process that is otherwise running correctly?

    • A.Soil raises the temperature that the whole load requires, so the cycle would succeed if the exposure phase were lengthened to compensate for the mass.
    • B.Soil is a cosmetic and corrosion problem that stains the finish, while the agent still reaches and kills the organisms lying beneath the deposit.
    • C.Soil consumes the indicator chemistry first, so the indicator fails to change even though the device underneath has in fact been fully processed.
    • D.Soil shields organisms from contact with the agent and can inactivate some chemistries, so the process never reaches what lies under the deposit.✓ Answer

    Disinfection and sterilization are surface phenomena: the agent must physically contact the organism. Organic matter forms a barrier over that surface and binds or neutralizes some agents, which is why no device can be disinfected or sterilized unless it is clean first.

    Source: CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, cleaning as a prerequisite to disinfection and sterilizationReport a problem with this question

19. 19. Lumened instruments sat soiled in a moist container over a weekend and biofilm has formed in the channels. What does this mean for reprocessing?

    • A.The matrix is destroyed in the sterilizer along with the organisms it holds, so its presence changes nothing once the set reaches a validated cycle.
    • B.The matrix dissolves in an enzymatic soak if it is given enough time, so a lengthened soak followed by the usual cycle returns the channels to clean.
    • C.The matrix protects the organisms it holds and has to be lifted by friction with a correctly sized brush, since soaking and disinfectant will not remove it.✓ Answer
    • D.The matrix forms only in the water lines of processing equipment, so instrument channels are unaffected and the set can follow the routine pathway.

    Biofilm is an adherent matrix that shelters the organisms inside it from germicides and blocks contact by the sterilant. It is removed physically, by brushing with a brush that fits the channel, which is also why point-of-use treatment and prompt cleaning matter.

    Source: CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, biofilm and its resistance to germicides; ANSI/AAMI ST79 point-of-use treatmentReport a problem with this question

20. 20. A technician is about to flush the channels of several lumened instruments with a pressurized water gun at the decontamination sink. What does this task require?

    • A.Fluid-resistant covering together with a mask and a full face shield, because the spray drives contaminated fluid into the air and toward the face.✓ Answer
    • B.The same protection as any other decontamination task, since the water gun draws on treated water that dilutes the soil it releases from a channel.
    • C.Safety glasses with side shields worn over a surgical mask, which is enough because the spray is directed down into the sink and away from the face.
    • D.A gown and gloves with the sink splash guard raised, since a fixed guard holds back spray from the gun better than anything worn on the body can.

    Personal protective equipment is selected for the splash and spray that the task can reasonably be expected to generate, not for the area in general. A pressurized flush aerosolizes contaminated fluid, so the eyes, nose, mouth and body all need a fluid-resistant barrier.

    Source: OSHA Bloodborne Pathogens Standard, 29 CFR 1910.1030, personal protective equipment for reasonably anticipated splash and sprayReport a problem with this question

21. 21. Over several weeks, trays from one procedure room have repeatedly arrived with heavy dried soil and no point-of-use treatment. What is the technician's correct course?

    • A.Add a longer enzymatic soak for that room's trays and keep processing them, since the problem is resolved once the soil comes off in decontamination.
    • B.Document the pattern and report it to the supervisor and to infection prevention, so the practice is corrected where the instruments are being used.✓ Answer
    • C.Raise it informally with the staff of that room at the next opportunity, and let the matter rest if the next several trays arrive in better condition.
    • D.Refuse further trays from that room until its staff have been retrained, and tell the room directly that its instruments are no longer being processed.

    A recurring failure upstream of the department is a quality and infection prevention issue that the technician cannot fix at the sink; dried soil raises the risk that a device leaves decontamination still soiled. The finding is documented and escalated so the root cause is addressed.

    Source: ANSI/AAMI ST79, quality process improvement and reporting of process failures; HSPA Sterile Processing Technical Manual, escalation through the chain of commandReport a problem with this question

22. 22. Instruments are returned from a procedure on a patient who is on contact precautions for Clostridioides difficile. What does this require of the department?

    • A.The set follows the routine pathway under standard precautions, since soiled items are already handled that way and the validated cycle inactivates spores.✓ Answer
    • B.The set is processed at the end of the day as a dedicated load, so that any spores released cannot reach the other instruments handled that shift.
    • C.The set is sent for a low-temperature method instead of steam, because the spores of this organism survive moist heat at the settings normally used.
    • D.The set is labeled infectious and soaked in a chlorine solution before cleaning, since ordinary detergents and cycles do not act on these spores.

    Every soiled item is already treated as infectious under standard precautions, and a validated sterilization process is designed to destroy bacterial spores. No separate protocol, segregated load or chlorine soak is indicated, which is what distinguishes this from prion cases.

    Source: CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, Clostridioides difficile: standard cleaning and sterilization are adequateReport 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 →