CRCST Cleaning, Decontamination and Disinfection Practice Test

25 practice questions

Choose an answer, then check it under Show answer.

1. Question 1 of 25Medium

   A glass container that came back on a case cart shatters in the decontamination sink. How should the technician remove the pieces?

   1. AA. By hand, one piece at a time, while wearing utility gloves
   2. BB. With tongs, forceps or a brush and dustpan
   3. CC. By pressing a wet sponge onto the pieces to lift them
   4. DD. By rinsing the pieces down the sink drain with running water
   Show answer to question 1

   Answer: B. With tongs, forceps or a brush and dustpan

   OSHA prohibits picking up possibly contaminated broken glass directly with the hands, even gloved; mechanical means such as tongs, forceps or a brush and dustpan are used. The pieces then go into a sharps container.

   Why the other options are wrong

   • AGloves do not stop glass cuts, and the standard bans picking up contaminated broken glass by hand.
   • CPressing a sponge onto broken glass can push fragments through it into the hand.
   • DRinsing glass into the drain can clog the plumbing and leaves sharps where others may later be injured.

2. Question 2 of 25Hard

   For the third time this week, sets from the same surgical service arrive in decontamination with dried blood and no sign of point-of-use treatment. What should the technician do?

   1. AA. Clean them as usual without comment, since some soil is expected
   2. BB. Refuse the sets until the service returns them properly treated
   3. CC. Report it to the surgeon by calling into the operating room at once
   4. DD. Pretreat and clean them, then report the pattern to the supervisor
   Show answer to question 2

   Answer: D. Pretreat and clean them, then report the pattern to the supervisor

   The sets still need careful processing, with dried soil pretreated as the instructions allow. A repeated point-of-use problem is reported to the supervisor, who can work with the surgical service to correct it.

   Why the other options are wrong

   • AStaying silent lets the problem continue, and dried soil raises the risk that instruments will not come clean.
   • BRefusing contaminated sets delays processing and leaves soiled items where they do not belong.
   • CCalling into a case interrupts the surgical team; the concern is raised through the supervisor instead.

3. Question 3 of 25Easy

   A central service technician is preparing a manual wash sink using an enzymatic detergent. Instead of using the calibrated proportioner or measuring cup, the technician pours an unmeasured, heavy amount of detergent into the sink. Why is using excessive detergent concentration detrimental to the cleaning process?

   1. AA. Excessive detergent leaves residual films that are difficult to rinse and can harbor microbes or cause tissue toxicity.
   2. BB. Excessive detergent creates heavy scale deposits that permanently block the sink drainage plumbing.
   3. CC. Excessive detergent causes immediate galvanic corrosion and pitting on all passive stainless steel surfaces.
   4. DD. Excessive detergent neutralizes the enzymes and prevents the breakdown of blood and organic proteins.
   Show answer to question 3

   Answer: A. Excessive detergent leaves residual films that are difficult to rinse and can harbor microbes or cause tissue toxicity.

   Using too much detergent makes thorough rinsing difficult, leaving behind residues that can lead to patient toxicity, interfere with subsequent sterilization, and harbor microorganisms. Although some technicians mistakenly believe higher chemical concentrations always clean faster or corrode metal instantly, excess concentration primarily creates rinsing problems and chemical buildup without improving cleaning efficacy.

4. Question 4 of 25Easy

   While sorting an orthopedic tray, a technician finds cut pieces of used stainless steel wire and a used drill bit labeled for single use. Where should these items go?

   1. AA. Into the red bag with the soiled sponges and drapes
   2. BB. Back into the tray to be cleaned with the instruments
   3. CC. Into a closable, puncture-resistant sharps container
   4. DD. Into the regular trash, wrapped in a paper towel
   Show answer to question 4

   Answer: C. Into a closable, puncture-resistant sharps container

   Used wire pieces and a used single-use drill bit are contaminated sharps. They go into a closable, puncture-resistant, leakproof sharps container that is labeled or color-coded, and they are not cleaned for reuse.

   Why the other options are wrong

   • ASharp pieces can pierce a plastic biohazard bag and injure anyone who handles it later.
   • BCut wire and a single-use drill bit are not reusable, so they are not cleaned for another patient.
   • DPaper does not stop punctures, and contaminated sharps never go into regular trash.

5. Question 5 of 25Medium

   When monitoring the quality of treated critical water, an increase in electrical conductivity indicates:

   1. AA. A decrease in dissolved oxygen levels
   2. BB. A drop in microbial endotoxin levels
   3. CC. A higher concentration of dissolved ions
   4. DD. An increase in water electrical resistance
   Show answer to question 5

   Answer: C. A higher concentration of dissolved ions

   Electrical conductivity measures the ability of water to carry an electrical current, which rises directly as dissolved mineral ions and salts increase. High conductivity signifies a decrease in water purity, whereas critical water should maintain low conductivity and correspondingly high resistivity.

6. Question 6 of 25Medium

   Why are single-use devices generally unsuitable for standard in-hospital cleaning and reprocessing protocols?

   1. AA. Their synthetic components interfere with chemical indicators during routine monitoring
   2. BB. Their materials and physical designs are not validated to withstand standard cleaning chemicals and heat
   3. CC. They lack individual laser-etched serial numbers needed for instrument tracking software
   4. DD. They are made strictly from low-grade metals that corrode immediately in neutral pH detergents
   Show answer to question 6

   Answer: B. Their materials and physical designs are not validated to withstand standard cleaning chemicals and heat

   Single-use devices are constructed and tested for a single patient application; they often feature tortuous lumens, specialized adhesives, or heat-sensitive polymers that cannot be reliably cleaned or re-sterilized without degradation. Reusable devices, by contrast, are engineered from robust materials and accompanied by validated manufacturer instructions for multi-cycle processing. Single-use devices are not banned simply because they lack serial numbers or react with chemical indicators.

7. Question 7 of 25Hard

   The IFU for a set of plastic instruments limits processing temperature to 60°C (140°F). The washer-disinfector's standard instrument cycle includes a thermal rinse at 90°C (194°F). What should the technician do?

   1. AA. Run the standard cycle and check the items for warping afterward
   2. BB. Stop the standard cycle by hand just before its thermal rinse starts
   3. CC. Use a washer cycle or manual method that stays within the IFU limit
   4. DD. Ask the supervisor to raise the IFU limit, then run the standard cycle
   Show answer to question 7

   Answer: C. Use a washer cycle or manual method that stays within the IFU limit

   Limits in a device IFU, such as a maximum temperature, must be respected, so the technician uses a washer cycle or manual method that the IFU allows. Heat beyond the limit can warp or weaken the device even when no damage is visible.

   Why the other options are wrong

   • AHeat damage may not be visible, and running a cycle the IFU forbids is not an acceptable test.
   • BStopping a cycle by hand leaves the process incomplete and does not create a validated cycle.
   • DOnly the device manufacturer sets the limits in its IFU, and the department cannot change them to fit a standard cycle.

8. Question 8 of 25Easy

   In AAMI guidance on water for processing medical devices, what is critical water?

   1. AA. Tap water heated to the temperature of the thermal rinse
   2. BB. Softened tap water used for the first rinse of soiled items
   3. CC. Water that meets drinking water standards at the tap
   4. DD. Water extensively treated, as by reverse osmosis
   Show answer to question 8

   Answer: D. Water extensively treated, as by reverse osmosis

   Critical water is extensively treated, for example by reverse osmosis, deionization or distillation, to remove microorganisms, endotoxins and dissolved minerals. It is used mainly for the final rinse of devices.

   Why the other options are wrong

   • AHeating tap water does not remove its dissolved minerals and other impurities.
   • BSoftened tap water is still utility water, suited to early cleaning steps rather than the final rinse.
   • CMeeting drinking water standards does not provide the purity needed for the final rinse of medical devices.

9. Question 9 of 25Medium

   A technician develops an itchy rash on both hands that employee health links to the department's latex utility gloves. Under the Bloodborne Pathogens Standard, what must the employer do?

   1. AA. Give her a heavier grade of latex utility glove, since thicker latex blocks the reaction
   2. BB. Have her apply a barrier cream under the latex gloves she uses now
   3. CC. Make nonlatex gloves or glove liners readily available to her
   4. DD. Move her out of decontamination until the rash completely heals
   Show answer to question 9

   Answer: C. Make nonlatex gloves or glove liners readily available to her

   The employer must make hypoallergenic gloves, glove liners, powderless gloves or similar alternatives readily accessible to workers who are allergic to the gloves normally provided, and all required PPE is supplied at no cost.

   Why the other options are wrong

   • AThicker latex still exposes her to latex; she needs nonlatex gloves or liners instead.
   • BA barrier cream does not remove the latex exposure, and the standard calls for alternative gloves or liners for workers allergic to the usual gloves.
   • DThe standard does not call for reassignment; suitable alternative gloves let her keep working safely in decontamination.

10. Question 10 of 25Medium

    According to OSHA regulations, which feature is required for all sharps disposal containers utilized in the surgical processing department?

    1. AA. A foot-pedal mechanism for hands-free operation
    2. BB. Clear, transparent walls to monitor fill volume
    3. CC. Removable interior liners for repeated autoclaving
    4. DD. Puncture-resistant and leakproof sides and bottom
    Show answer to question 10

    Answer: D. Puncture-resistant and leakproof sides and bottom

    OSHA mandates that all sharps disposal containers must be puncture-resistant, leakproof on the sides and bottom, closable, and properly labeled or color-coded. Containers are not required to be transparent or foot-pedal operated, and sharps containers must be rigid single-use or specially designed reusable units rather than lined with autoclavable bags.

11. Question 11 of 25Medium

    To save time, a technician wants to put a tray of instruments still coated with blood and tissue straight into the ultrasonic cleaner. What is the best response?

    1. AA. That is fine, because cavitation works best on heavy soil
    2. BB. Remove gross soil first, since heavy soil reduces cavitation
    3. CC. Add extra detergent so the heavy soil dissolves in the tank
    4. DD. Run two ultrasonic cycles in a row in place of precleaning
    Show answer to question 11

    Answer: B. Remove gross soil first, since heavy soil reduces cavitation

    Ultrasonic cleaning is meant for fine soil in hard-to-reach areas after gross soil has been removed. Heavy soil absorbs the ultrasonic energy and quickly contaminates the solution, so items are precleaned first.

    Why the other options are wrong

    • AHeavy soil dampens cavitation rather than helping it, so fine soil is left behind.
    • CExtra detergent does not overcome heavy soil and leaves residue that is harder to rinse off.
    • DRepeating cycles in heavily soiled solution can redeposit soil and does not replace precleaning.

12. Question 12 of 25Easy

    Who bears the primary responsibility for separating disposable items, gross soil, and sharps from reusable instrument sets immediately following a surgical procedure?

    1. AA. The operating room environmental services worker
    2. BB. The scrub person at the point of use
    3. CC. The sterile processing packaging technician
    4. DD. The central service decontamination technician
    Show answer to question 12

    Answer: B. The scrub person at the point of use

    AORN and ANSI/AAMI ST79 guidelines state that point-of-use preparation must be performed by the scrub person (surgical technologist or scrub nurse) in the operating room, which includes removing sharps, disposables, and gross debris prior to transport. While decontamination technicians sort and clean trays upon arrival, relying on central service personnel to discover and remove contaminated sharps significantly increases sharps injury risks.

13. Question 13 of 25Medium

    A technician plans to run a basket of stainless steel instruments mixed with several brass and aluminum instrument parts through the ultrasonic cleaner. What is the concern with this load?

    1. AA. Dissimilar metals can react, causing etching, staining or plating
    2. BB. Brass and aluminum need a separate, hotter cycle to come clean
    3. CC. Stainless steel absorbs the energy, leaving little for the softer metals
    4. DD. The softer metal parts sink to the bottom, out of the cleaning zone
    Show answer to question 13

    Answer: A. Dissimilar metals can react, causing etching, staining or plating

    Instruments of dissimilar metals are not processed together in an ultrasonic cleaner, because metal ions can transfer from one metal to another through the cleaning solution. This electrolytic transfer can etch, stain or plate the instruments.

    Why the other options are wrong

    • BThe concern is a reaction between metals, not temperature, and cycle settings come from the IFU rather than from metal softness.
    • CStainless steel does not draw energy away from other items; the problem is a reaction between dissimilar metals.
    • DEverything in the basket sits fully under the solution, so where the parts settle is not the problem.

14. Question 14 of 25Medium

    After a case, the vendor representative asks to take a used loaner instrument set straight from the operating room back to the company. What should happen first?

    1. AA. Wipe the set with a disinfectant cloth and hand it over in the hallway
    2. BB. Let the vendor take it, since the company cleans its own instruments
    3. CC. Seal the soiled set in a biohazard bag and release it without cleaning
    4. DD. Clean and decontaminate it in the SP department before it is released
    Show answer to question 14

    Answer: D. Clean and decontaminate it in the SP department before it is released

    Used loaner sets are decontaminated in the SP department before they leave the facility, which protects the vendor's staff and anyone else who handles them. OSHA expects contaminated equipment to be decontaminated before shipping whenever that is feasible.

    Why the other options are wrong

    • AA quick wipe does not clean the instruments, and handing a soiled set over in a hallway spreads contamination.
    • BThe facility used the set, so it is responsible for decontaminating it before anyone outside handles it.
    • CBagging does not make a soiled set safe, and because decontamination is feasible here, it must come first.

15. Question 15 of 25Hard

    An eye surgery list has many cataract cases in a row, and the department owns only two phacoemulsification instrument sets. Staff are being pressed to shorten cleaning and rinsing steps to keep up. What should the technician do?

    1. AA. Shorten the rinse steps, since the sets will be steam sterilized next
    2. BB. Skip the hand flushing the IFU lists and rely on the washer cycle
    3. CC. Ask the supervisor to approve IUSS for the sets without full cleaning
    4. DD. Report to the supervisor that the sets cannot be fully processed in time
    Show answer to question 15

    Answer: D. Report to the supervisor that the sets cannot be fully processed in time

    Shortcuts in cleaning and rinsing intraocular instruments between back-to-back cases are a known contributor to TASS, so every step in the IFU is completed for each set. The technician reports the conflict so the supervisor can add sets or adjust the schedule instead of cutting steps.

    Why the other options are wrong

    • ASteam sterilization does not remove detergent, viscoelastic or other residues, so rinse steps cannot be shortened.
    • BSkipping IFU steps leaves residue in fine cannulated instruments, which a washer cycle alone may not remove.
    • CNo approval makes it acceptable to sterilize intraocular instruments that have not been fully cleaned and rinsed.

16. Question 16 of 25Medium

    How should reusable cleaning brushes be handled after use at the decontamination sinks?

    1. AA. Clean them, then disinfect or sterilize them as the brush IFU directs
    2. BB. Rinse them under running tap water and hang them to air-dry for reuse
    3. CC. Leave them soaking in the used detergent solution until the next shift
    4. DD. Soak them for the time the detergent IFU lists, then put them back in use
    Show answer to question 16

    Answer: A. Clean them, then disinfect or sterilize them as the brush IFU directs

    Used brushes carry soil and microorganisms, so reusable brushes are cleaned and then disinfected or sterilized as their IFU directs, and they are checked for wear before reuse.

    Why the other options are wrong

    • BRinsing removes some soil but does not disinfect, so the brush can carry microorganisms to the next instrument.
    • CUsed detergent solution is contaminated, and microorganisms can multiply on bristles left in it.
    • DA detergent soak cleans but does not disinfect, so the brush is still not safe to reuse.

17. Question 17 of 25Medium

    Before the first use of the day, the minimum effective concentration (MEC) test strip for a glutaraldehyde basin shows a fail result. The solution is still within its reuse life. What should the technician do?

    1. AA. Keep using it, but soak each device longer than the label time
    2. BB. Add concentrate to the solution until a new strip passes
    3. CC. Use it today, since it is still within its labeled reuse life
    4. DD. Discard it, then refill and test the fresh solution before use
    Show answer to question 17

    Answer: D. Discard it, then refill and test the fresh solution before use

    A failed MEC test means the solution may be too weak for high-level disinfection, so it is discarded even within its reuse life. The fresh solution is tested before use, and the failure and the corrective action are recorded.

    Why the other options are wrong

    • AA longer soak does not make up for low concentration, and staff may not change label conditions.
    • BAdding concentrate to a used solution is not a practice the label supports, and it leaves the true strength uncertain.
    • CBeing within the reuse life does not make a weak solution effective, so a failed MEC test ends its use at once.

18. Question 18 of 25Hard

    A washer-disinfector has stopped with the same pump fault alarm three times this morning, and each time a coworker reset it and started the cycle again. What should the technician do now?

    1. AA. Reset it again and report the alarm at the end of the shift
    2. BB. Tag it out of service and report the repeated alarm for repair
    3. CC. Bypass the alarm in the settings menu so cycles run without stopping
    4. DD. Keep using it for lightly soiled loads until the shift ends
    Show answer to question 18

    Answer: B. Tag it out of service and report the repeated alarm for repair

    A fault that keeps returning shows the washer is not working reliably, so it is tagged out of service and reported for repair. Loads from the interrupted cycles are reprocessed.

    Why the other options are wrong

    • AMore resets keep a faulty washer in use and delay the repair it needs.
    • CBypassing an alarm defeats a safety and quality control and is not an operator task.
    • DA faulty washer cannot be relied on to clean any load, whether light or heavy.

19. Question 19 of 25Easy

    Which type of chemical disinfectant is commonly used for routine low-level disinfection of noncritical surfaces such as countertops, carts and equipment housings?

    1. AA. Glutaraldehyde solution
    2. BB. Ortho-phthalaldehyde (OPA) solution
    3. CC. Quaternary ammonium compound
    4. DD. Peracetic acid sterilant concentrate
    Show answer to question 19

    Answer: C. Quaternary ammonium compound

    Quaternary ammonium compounds are widely used as low-level disinfectants for noncritical environmental surfaces and equipment. They clean well but are not used for high-level disinfection of semicritical devices.

    Why the other options are wrong

    • AGlutaraldehyde is a high-level disinfectant for semicritical devices, and its irritating vapor makes it unsuitable for routine surface wiping.
    • BOPA is a high-level disinfectant for soaking semicritical devices, not a product for wiping countertops and carts.
    • DPeracetic acid concentrate is used as a sterilant or high-level disinfectant for devices, not for wiping countertops and carts.

20. Question 20 of 25Easy

    When loading deep, solid-bottom basins and bowls into a washer-disinfector rack, how should they be oriented?

    1. AA. Inverted or tilted downward to allow thorough washing and complete drainage
    2. BB. Upright with open rims facing upward toward the top spray arm
    3. CC. Placed flat on bottom shelves with moisture-absorbent medical tray liners
    4. DD. Nested tightly together in matching sets to optimize chamber space
    Show answer to question 20

    Answer: A. Inverted or tilted downward to allow thorough washing and complete drainage

    Hollowware such as basins, bowls, and receivers must be placed upside down or angled diagonally so that wash water enters the cavity and drains freely without pooling. Orienting them upright leads to heavy pooling of dirty water and prevents proper drying and thermal disinfection.

21. Question 21 of 25Hard

    According to national professional standards (such as ANSI/AAMI ST91), which feature is recommended for a dedicated cabinet used to store flexible endoscopes?

    1. AA. Positive-pressure airflow supplied with HEPA-filtered air
    2. BB. High relative humidity above 70% to preserve the flexibility of polymer sheaths
    3. CC. Continuous negative pressure to vent chemical vapors to outside ducts
    4. DD. Continuous ultraviolet germicidal irradiation across all interior surfaces
    Show answer to question 21

    Answer: A. Positive-pressure airflow supplied with HEPA-filtered air

    Drying and storage cabinets for flexible endoscopes should provide positive-pressure, HEPA-filtered air to ensure clean air is constantly moving past the hung instruments and preventing ambient room contaminants from entering. Negative pressure would draw room dust and microorganisms into the cabinet, and high humidity encourages microbial proliferation on stored devices.

22. Question 22 of 25Hard

    During point-of-use treatment of lumened devices such as Frazier suction tips, what is the correct method to prepare the channels for transport?

    1. AA. Occlude both ends of each lumen with elastomeric caps to prevent fluid escape
    2. BB. Flush the lumens with sterile water or an approved enzymatic solution
    3. CC. Instill 70% isopropyl alcohol into the channels to coagulate inner bioburden
    4. DD. Pack dry gauze tightly into the suction tips to absorb residual moisture
    Show answer to question 22

    Answer: B. Flush the lumens with sterile water or an approved enzymatic solution

    Cannulated items must be flushed with sterile water or an enzymatic solution at the point of use to expel gross debris and prevent inner soil from drying before automated or manual cleaning. Alcohol must never be applied because it coagulates and fixes proteins to internal surfaces, making decontamination significantly harder.

23. Question 23 of 25Medium

    Which brush is the right choice for cleaning a long, narrow lumen that is open at both ends?

    1. AA. The department's standard lumen brush, whatever the lumen size
    2. BB. A thin brush that slides through easily, so its bristles stay straight
    3. CC. A brush that touches the walls all around and can exit the far end
    4. DD. The brush with the stiffest bristles available, to scrape the walls clean
    Show answer to question 23

    Answer: C. A brush that touches the walls all around and can exit the far end

    The bristles must contact the whole inner wall to scrub soil away, and the brush must travel the full length and come out the far end so no section is missed. The device IFU often states the brush size to use.

    Why the other options are wrong

    • AOne brush cannot fit every lumen; a small one misses the walls and an oversized one crushes its bristles.
    • BBristles that slide through without contacting the walls cannot scrub off soil that clings to them.
    • DStiffness does not make up for poor fit, and stiff bristles can scratch the lumen and leave places where soil collects.

24. Question 24 of 25Hard

    ANSI/AAMI ST79 and CDC guidelines state that while high-level disinfection is the minimum standard for semicritical items, what is the preferred reprocessing method for semicritical devices that are heat-tolerant?

    1. AA. Low-temperature hydrogen peroxide gas plasma processing
    2. BB. Liquid chemical sterilization using extended glutaraldehyde soaks
    3. CC. High-level chemical disinfection in an automated endoscope reprocessor
    4. DD. Steam sterilization in an appropriate validated cycle
    Show answer to question 24

    Answer: D. Steam sterilization in an appropriate validated cycle

    CDC and AAMI guidelines explicitly recommend that if a semicritical item can tolerate heat and moisture, steam sterilization is the preferred method because it provides the highest margin of safety. While high-level disinfection meets the minimum standard for semicritical items, it is not the preferred method when thermal sterilization can be safely applied.

25. Question 25 of 25Easy

    Before a soiled case cart is pushed into the cart washer, what must the technician do?

    1. AA. Remove all instruments, trash and loose items from the cart
    2. BB. Leave the soiled trays inside so they are washed with the cart
    3. CC. Close and latch every door so the spray cleans only the outside
    4. DD. Spray the cart with disinfectant so the washer can skip its rinse
    Show answer to question 25

    Answer: A. Remove all instruments, trash and loose items from the cart

    A cart washer is designed to clean the cart itself, so every instrument, tray, trash item and loose object is removed first. Anything left inside blocks the spray, can be damaged, and is not properly cleaned by a cart cycle.

    Why the other options are wrong

    • BInstrument trays need their own validated cleaning process, and a cart cycle is not meant to clean trays left inside a cart.
    • CThe inside of a case cart is soiled too, and closed doors keep the spray from reaching its shelves and walls.
    • DSpraying disinfectant first does not replace any phase of the cart washer's validated cycle.

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