HSPA Sterile Processing (CRCST) — All Questions

A surgical case has just ended and the scrub person is preparing instruments for transport to the decontamination area. What is the correct point-of-use treatment?

• a.Perform a full manual wash at the sterile field before transport
• b.Allow the instruments to air dry so blood flakes off during transport
• c.Spray the instruments with saline and wrap them in a dry towel
• d.Remove gross soil and keep the instruments moist until they reach decontamination✓

Point-of-use treatment means wiping away gross soil and applying a moisture-retention product or damp towel so bioburden does not dry onto surfaces. Dried blood and protein are far harder to remove and can block sterilant contact. Saline is corrosive to instrument alloys, and full cleaning is never performed in the operating room because it creates contaminated aerosols in a sterile environment.AAMI ST79

A new employee asks why the department never uses saline to soak or moisten soiled surgical instruments. What is the correct explanation?

• a.It neutralizes enzymatic detergent and stops protein breakdown
• b.The chloride ions attack the passive layer and cause pitting and corrosion✓
• c.It coagulates protein soil onto the instrument surface
• d.It raises the pH of the soak bath above the safe range for stainless steel

Sodium chloride breaks down the chromium oxide passive layer that protects stainless steel, producing pitting, staining, and eventual instrument failure. Water with an appropriate presoak or enzymatic product is the correct choice. Protein coagulation is caused by heat, not saline, and pH shift is not the mechanism of chloride damage.AAMI ST79

What air pressure relationship should the decontamination area have compared with adjacent areas of the department?

• a.Positive pressure, so clean air is pushed toward the soiled workroom
• b.Negative pressure, so contaminated air does not flow into clean areas✓
• c.Alternating pressure controlled by the sterilizer cycle
• d.Equal pressure, so no air movement occurs between rooms

The decontamination room is held at negative pressure so airborne contaminants and aerosols generated during cleaning are drawn out and exhausted rather than escaping into preparation, packaging, or sterile storage. Positive pressure is used in the clean workroom and sterile storage. Equal or alternating pressure would allow uncontrolled migration of contaminated air.AAMI ST79

A facility engineer rebalancing the ventilation system asks the technician what governs the decontamination area's air exchange rate. What is the accurate answer?

• a.The rate is set by ANSI/ASHRAE/ASHE 170 in the edition in force for that system✓
• b.The rate is fixed at four air exchanges per hour in every reprocessing area
• c.The rate is chosen by the department based on how busy the workload is
• d.The rate is set permanently by AAMI ST79 and does not change between editions

AAMI ST79:2017 removed its own HVAC values and defers to ANSI/ASHRAE/ASHE 170 in the edition in force when the system was installed or last upgraded, so the governing number depends on that edition rather than on a figure memorized from an older text. The widely repeated 10 air changes per hour is pre-2017 AAMI legacy and is associated with the sterilizer equipment room, not decontamination. A fixed four per hour is the sterile-storage figure, not a universal reprocessing rate. The department cannot set it by workload — it is an engineered requirement verified by testing. And ST79 no longer fixes it permanently, which is exactly the change that makes the old memorized numbers unreliable. What does not move between editions is the pressure relationship: decontamination is kept negative to adjacent spaces, and clean workrooms and sterile storage positive.AAMI ST79 · ANSI/ASHRAE/ASHE 170

A facility engineer asks what temperature range the decontamination area should be maintained within. What is the correct answer?

• a.68 to 73 degrees F (20 to 23 degrees C)
• b.60 to 65 degrees F (16 to 18 degrees C)✓
• c.75 to 80 degrees F (24 to 27 degrees C)
• d.Any temperature that staff find comfortable in personal protective equipment

The decontamination area is kept cooler, roughly 60 to 65 degrees F, because staff work in full impervious personal protective equipment and the cooler air limits heat stress and microbial growth. The 68 to 73 degrees F range applies to the preparation and packaging area. Storage areas should not exceed about 75 degrees F, and comfort alone is not an acceptable engineering control.AAMI ST79

During a survey, an inspector reviews the department's daily environmental logs and asks what relative humidity range must be maintained in the work areas. What is correct?

• a.10 to 25 percent
• b.Humidity does not need to be monitored in decontamination
• c.65 to 80 percent
• d.30 to 60 percent✓

Relative humidity of roughly 30 to 60 percent limits microbial growth and static electricity while protecting packaging materials from moisture damage. Very low humidity dries out wrappers and generates static; humidity above 60 percent supports microbial proliferation and can cause packaging and stored items to absorb moisture. Humidity must be monitored and documented in all reprocessing areas, including decontamination.AAMI ST79

A technician is about to begin manual cleaning at an open sink where splashing is expected. Which personal protective equipment combination is required?

• a.A sterile gown and sterile gloves, because the instruments are contaminated
• b.A cloth lab coat, gloves, and eyeglasses
• c.Fluid-resistant gown, general-purpose utility gloves, face mask with eye protection or a full face shield, and hair covering✓
• d.Gloves and a surgical mask only

OSHA requires personal protective equipment that prevents blood or other potentially infectious material from reaching skin, mucous membranes, or street clothes, which at a decontamination sink means a fluid-resistant gown, heavy utility gloves, face and eye protection, and hair covering. Personal eyeglasses are not eye protection because they lack side and splash shielding. Sterile attire is irrelevant in decontamination, where the goal is worker protection, not product protection.OSHA 29 CFR 1910.1030

A technician is orienting a student at the ultrasonic cleaner and is asked what actually removes the soil from the instruments. What is the correct answer?

• a.Thermal disinfection at the final rinse temperature
• b.High-velocity water jets directed at instrument surfaces
• c.Cavitation, in which microscopic bubbles form and implode against instrument surfaces✓
• d.Chemical oxidation of protein by the detergent

High-frequency sound waves create low-pressure zones where tiny bubbles form and then collapse, and the energy released by that implosion dislodges fine soil from crevices, box locks, and serrations. Thermal disinfection and spray-jet impingement are mechanisms of washer-disinfectors, not ultrasonic units. Detergent assists cavitation but is not itself the cleaning action.AAMI ST79

An ultrasonic cleaner has just been filled with fresh solution at the start of the shift. Why must the unit be degassed before instruments are processed?

• a.Degassing sterilizes the solution so instruments leave the unit sterile
• b.Degassing removes residual detergent from the previous shift
• c.Degassing raises the solution to the required thermal disinfection temperature
• d.Dissolved air in fresh solution cushions the sound waves and prevents effective cavitation✓

Fresh water holds dissolved gas that absorbs ultrasonic energy and dampens bubble formation, so the unit is run empty for several minutes to drive the gas out and restore full cavitation. Degassing is not a heating, rinsing, or sterilizing step. An ultrasonic cleaner never sterilizes; it is a cleaning device only.AAMI ST79

A technician loads a mixed basket of stainless steel clamps, chrome-plated retractors, and aluminum instruments into the ultrasonic cleaner. What is the problem with this load?

• a.Aluminum instruments cannot be cleaned by any mechanical method
• b.The basket exceeds the maximum weight rating of the transducer
• c.Chrome-plated instruments must be processed in the ultrasonic twice
• d.Mixing dissimilar metals in the same ultrasonic bath can cause electrolytic corrosion and plating transfer✓

When different metals sit in the same conductive bath, ions migrate between them and produce staining, etching, and plating deposits, so instruments should be sorted by metal type. Aluminum can be mechanically cleaned when a compatible neutral or low-alkaline detergent is used. Weight rating and double processing are not the concerns raised by a mixed-metal load.AAMI ST79

A technician fills the wash sink with very hot water to speed up cleaning. Why must manual cleaning water stay below approximately 140 degrees F (60 degrees C)?

• a.Higher temperatures cause the detergent to foam excessively and overflow the sink
• b.Higher temperatures make it impossible to see instruments below the water line
• c.Higher temperatures deactivate the chlorides that dissolve blood
• d.Heat above that point coagulates protein soil and bonds it to the instrument surface✓

Protein denatures and coagulates with heat, so hot water effectively bakes blood and tissue onto instruments and makes removal much harder. Enzymatic detergents also lose activity outside the temperature window on the label. Foaming, visibility, and chloride activity are not the reason for the temperature limit.AAMI ST79

Most instrument manufacturers specify a neutral pH detergent for routine cleaning. What pH range is considered neutral?

• a.pH 4 to 6
• b.pH 1 to 4
• c.pH 6 to 8✓
• d.pH 9 to 11

Neutral detergents fall roughly between pH 6 and 8 and are the safest choice for the widest range of instrument materials, including anodized aluminum and delicate coatings. Strongly acidic products near pH 1 to 4 are reserved for removing mineral scale and rust deposits, and highly alkaline products near pH 9 to 11 attack aluminum and certain finishes even though they cut heavy soil. Selection must always follow the device manufacturer instructions for use.AAMI ST79

A washer-disinfector is being validated and the question arises about which water quality is required for the final rinse. What is correct?

• a.Distilled water heated to at least 180 degrees F but not otherwise treated
• b.Critical water, which has been treated to remove minerals, ions, and endotoxins✓
• c.Softened water only, with no additional treatment
• d.Utility water straight from the municipal tap

Critical water is extensively treated by processes such as reverse osmosis or deionization so that the final rinse does not deposit minerals, ions, or endotoxin residues on devices that will contact sterile tissue. Utility water is acceptable for flushing, washing, and initial rinsing but leaves residues on the final product. Softening alone removes hardness ions but not the full range of contaminants, and temperature does not substitute for treatment.AAMI ST79

A technician is scrubbing a hinged instrument with a brush at the decontamination sink and is spraying water droplets into the air. What is the correct technique?

• a.Brush above the water line so soil is visible and can be rinsed away immediately
• b.Brush more slowly under a running faucet so droplets fall back into the sink
• c.Substitute a high-pressure water gun for the brush at all times
• d.Keep the instrument and the brush fully submerged beneath the water surface while brushing✓

Brushing under the surface of the water contains splash and prevents the release of contaminated aerosols that expose the worker and the room air. Working above the water line, even slowly under a faucet, still generates droplets. Pressurized water guns have their place for lumens but must be used with additional splash protection and do not replace submerged brushing.AAMI ST79

What is the purpose of the elevated-temperature rinse phase, often around 180 degrees F or higher, in a washer-disinfector cycle?

• a.It cools the load gradually to prevent thermal shock to delicate instruments
• b.It sterilizes the instruments so they can bypass terminal sterilization
• c.It activates the enzymatic detergent so proteins continue to break down
• d.It provides thermal disinfection that reduces microbial load and improves drying✓

The hot rinse delivers thermal disinfection, lowering the bioburden so items can be safely handled in the clean workroom, and the residual heat helps the load dry. Thermal disinfection is not sterilization, so terminal sterilization is still required for critical devices. Enzymes are destroyed at that temperature, and the phase heats rather than cools the load.AAMI ST79

A department is writing its quality plan and must set a frequency for cleaning verification testing of its mechanical washers. What should the plan specify?

• a.At least weekly, and preferably each day the washer is used✓
• b.Once per month, at the start of the month
• c.Once per quarter, at the same time as preventive maintenance
• d.Only when a visible soil complaint is reported by the operating room

Routine cleaning verification with a commercial soil test device confirms the washer is still removing soil, and the recommendation is at least weekly with daily testing preferred. Waiting for a complaint is reactive and allows contaminated devices to reach patients. Quarterly and monthly intervals are too infrequent to catch a spray arm blockage, pump failure, or chemical delivery problem in time.AAMI ST79

A new sterile processing department is being designed. Which statement describes correct workflow?

• a.Work flows in one direction only, from soiled receiving through decontamination to clean assembly, sterilization, and storage✓
• b.Staff may move freely between decontamination and assembly as long as gloves are changed
• c.Clean and soiled items may share a corridor as long as they travel at different times of day
• d.Sterilizer loading may occur from either the clean or the soiled side depending on staffing

Unidirectional flow with physical separation between soiled and clean areas is the fundamental design principle that prevents recontamination of processed items. Time separation on a shared corridor does not remove residual contamination or airborne risk. Moving between areas requires full removal of protective attire and hand hygiene, not just a glove change, and sterilizers are always loaded from the clean side.AAMI ST79

Soiled instruments must be transported from the operating room to the decontamination area on a different floor. What is required?

• a.A rigid sterilization container with the filters removed for ventilation
• b.An open cart covered with a clean sheet and moved by the fastest route
• c.A closed or covered leak-proof container or cart labeled with a biohazard symbol or color coded✓
• d.Sealed plastic bags placed inside a food-service transport cart

OSHA requires contaminated items to be transported in containers that prevent leakage and are labeled or color coded so anyone encountering them knows the contents are biohazardous. A cloth sheet is not leak proof and does not warn other staff. Sterilization containers are not soiled-transport containers, and mixing biohazard transport with food-service equipment is prohibited.OSHA 29 CFR 1910.1030

A decontamination area is equipped with three sinks. What is the intended use of each?

• a.Rinse, disinfect, and lubricate
• b.Soak, sterilize, and dry
• c.Presoak, ultrasonic, and inspection
• d.Wash, intermediate rinse, and final rinse✓

The standard three-sink configuration separates the wash bath from an intermediate rinse and then a final rinse, usually with treated water, so detergent and loosened soil are not carried forward onto clean items. Sterilization, disinfection, and lubrication never take place in a decontamination sink. Ultrasonic cleaning and inspection are done in dedicated equipment and areas, not in the sink bays themselves.AAMI ST79

A lumened suction instrument arrives in decontamination. Which cleaning practice is correct?

• a.Flush the channel with detergent solution and brush it with a brush of the correct diameter and length, then rinse thoroughly✓
• b.Soak the device for one hour and rely on the soak to clear the lumen
• c.Run the device through the ultrasonic cleaner only, since brushes cannot reach the channel
• d.Flush the lumen with a high-pressure air gun before any liquid contacts the device

Lumens require mechanical action delivered by a brush that actually contacts the internal wall along the full channel length, followed by thorough flushing and rinsing. A brush that is too small does not touch the walls and one that is too large cannot pass. Soaking alone, ultrasonic alone, or blowing air through a dry contaminated channel will not remove adherent biofilm and soil.AAMI ST79

Instrument sets are consistently arriving in decontamination with hard, dried blood in box locks and serrations. What is the most likely root cause?

• a.The decontamination area humidity is above 60 percent
• b.Point-of-use treatment is not being performed and the sets sit too long before processing✓
• c.The transport carts are being covered too tightly
• d.The washer-disinfector detergent concentration is set too high

Dried, baked-on soil is the classic signature of missing point-of-use treatment combined with delayed transport, and the fix is education of the procedural areas plus prompt pickup. Excess detergent does not create dried soil, and it would be observed after washing rather than on arrival. High humidity would tend to keep soil moist, and covering carts protects rather than harms the instruments.AAMI ST79

A technician keeps a covered coffee cup on a shelf above the decontamination sink. How should this be addressed?

• a.It is acceptable because the cup has a lid and is not on the work surface
• b.It is acceptable if the technician removes gloves before drinking
• c.It is prohibited because eating, drinking, and storing food or drink are not allowed where occupational exposure occurs✓
• d.It is prohibited only if the cup is within the splash zone of the sink

OSHA bans eating, drinking, smoking, applying cosmetics, handling contact lenses, and storing food or drink in any area where occupational exposure to blood or other potentially infectious material is reasonably anticipated. A lid does not protect against contaminated aerosols settling on the exterior of the container. Glove removal and distance from the sink do not create an exemption.OSHA 29 CFR 1910.1030

Instruments are coming out of the washer with a chalky white film. Water testing shows high hardness. What is the appropriate corrective action?

• a.Increase the alkaline detergent concentration to dissolve the film
• b.Lower the final rinse temperature so minerals stay in solution
• c.Extend the wash phase by ten minutes on every cycle
• d.Address water quality with treatment such as softening or deionization, and use a descaling product as directed for existing deposits✓

A white chalky film is mineral scale from hard water depositing during rinsing and drying, and the durable fix is treating the water supply, with an acidic descaler used per manufacturer instructions to remove existing buildup. Adding alkaline detergent does not dissolve mineral scale and risks damaging aluminum. Longer wash times and cooler rinses do not change the mineral content of the water.AAMI ST79

An enzymatic cleaner label lists protease, lipase, and amylase. What does this combination indicate?

• a.The product will disinfect as well as clean
• b.The product can be used at any temperature without losing effectiveness
• c.The product targets several soil types, breaking down protein, fat, and starch or carbohydrate residues✓
• d.The product is intended for use only in ultrasonic cleaners

Each enzyme acts on a specific substrate, so protease attacks protein such as blood and tissue, lipase attacks fatty deposits, and amylase attacks starches and carbohydrates. Enzymatic cleaners clean but do not disinfect or sterilize. They are used in sinks and mechanical equipment alike, and their activity is temperature dependent and destroyed by hot water.AAMI ST79

A technician finishes cleaning and is about to walk into the clean assembly area. What must occur?

• a.Walk through quickly while holding the door with an elbow to avoid touching surfaces
• b.Keep the gown on but remove gloves, since the gown protects the clean area
• c.Remove all personal protective equipment in the decontamination area, dispose of or store it properly, and perform hand hygiene before entering✓
• d.Change gloves only, because the rest of the attire has not touched instruments

Protective attire worn in decontamination is considered contaminated and must be removed before leaving the area, followed by hand hygiene, so contamination is not carried into the clean workroom. A worn gown is a contaminated item, not a barrier that protects clean space. Speed and elbow technique do not remove contamination from attire or hands.OSHA 29 CFR 1910.1030

A case cart cannot be picked up for several hours because of staffing. What is the best interim measure for the soiled instruments?

• a.Wrap the set in a saline-dampened towel
• b.Apply an instrument pre-treatment foam, spray, or moisture-retaining product per the manufacturer instructions and keep the set covered✓
• c.Place the set in a warming cabinet so soil stays soft
• d.Immerse the entire set in a covered basin of tap water until pickup

Pre-treatment products are designed to hold moisture against the soil for extended periods and prevent it from drying, which preserves cleanability during unavoidable delays. Full immersion in open basins creates heavy containers, splash risk, and possible corrosion, and standing water can support microbial growth. Saline damages instruments, and heat accelerates drying and can coagulate protein.AAMI ST79

Why should the lid of an ultrasonic cleaner remain closed while the unit is running?

• a.To contain the contaminated aerosols that the cavitation process releases into the air✓
• b.To keep instruments from floating out of the basket
• c.To prevent the detergent from evaporating and changing concentration
• d.To maintain the water temperature required for thermal disinfection

Cavitation drives contaminated droplets off the solution surface, so keeping the lid closed protects staff and the room air from aerosolized bioburden. Ultrasonic cleaners do not perform thermal disinfection. Evaporation and floating instruments are minor operational issues, not the safety-driven reason for the closed lid.AAMI ST79

During a competency review, a technician is asked to explain why cleaning is considered the single most important step in instrument reprocessing. Which answer is correct?

• a.Cleaning is required only for instruments that will be used on sterile tissue
• b.Residual soil shields microorganisms from the sterilant, so an item that is not clean cannot be reliably sterilized✓
• c.Cleaning is what actually kills the spores present on the instrument
• d.Cleaning removes the need for a chemical indicator inside the package

Blood, tissue, and biofilm form a physical barrier that sterilant cannot penetrate, so any organism protected under residual soil may survive a technically correct sterilization cycle. Cleaning itself does not kill spores; it removes and reduces bioburden so the sterilant can work. Indicators monitor the process and cannot compensate for poor cleaning, and every reusable device requires cleaning regardless of its Spaulding classification.AAMI ST79

What is the fundamental difference between a gravity displacement cycle and a dynamic-air-removal (prevacuum) cycle?

• a.Gravity operates at a lower temperature than any dynamic-air-removal cycle
• b.Gravity uses saturated steam and dynamic-air-removal uses dry heat
• c.Gravity relies on incoming steam to push air down and out the drain, while dynamic-air-removal uses vacuum pulses to actively pull air out before steam is admitted✓
• d.Gravity requires a biological indicator while dynamic-air-removal does not

In a gravity cycle, steam entering the chamber displaces cooler, heavier air downward through the drain, which is slower and less reliable for porous items and lumens. Dynamic-air-removal cycles mechanically evacuate air with vacuum pulses or steam flushes so steam contacts every surface almost immediately. Both cycles use saturated steam, both are monitored with biological indicators, and both can run at 270 degrees F.AAMI ST79

A wrapped instrument set is being sterilized in a dynamic-air-removal steam sterilizer at 270 degrees F (132 degrees C). What is the typical minimum exposure time?

• a.1 minute
• b.15 minutes
• c.30 minutes
• d.4 minutes✓

Four minutes at 270 degrees F is the commonly validated exposure time for wrapped goods in a dynamic-air-removal cycle because air is removed before the exposure phase begins. Fifteen minutes at 270 degrees F and thirty minutes at 250 degrees F are gravity cycle parameters, which take longer because air removal is passive. One minute is not a validated exposure time for any wrapped steam cycle, and the device manufacturer instructions always govern the final selection.AAMI ST79

What is a standard gravity displacement steam cycle for a wrapped instrument set at 250 degrees F (121 degrees C)?

• a.60 minutes
• b.3 minutes
• c.30 minutes✓
• d.10 minutes

At the lower temperature of 250 degrees F, a gravity cycle needs about 30 minutes of exposure to achieve the required lethality, plus drying time. Shorter exposures of 3 or 10 minutes do not deliver sufficient lethality at that temperature for a wrapped set. Sixty minutes exceeds the validated requirement and unnecessarily stresses instruments; time and temperature are inversely related, so higher temperature permits shorter exposure.AAMI ST79

A technician opens the department at the start of the day shift and must schedule the Bowie-Dick test for a dynamic-air-removal sterilizer. How often is the test required?

• a.Each day the sterilizer is used, in the first cycle of the day after the warm-up cycle✓
• b.Only after a repair to the vacuum pump
• c.In every load that contains an implant
• d.Once per week, on the same day each week

The Bowie-Dick test verifies air removal and steam penetration and is run daily in an otherwise empty chamber before the first processed load, typically after a warm-up cycle. It is an air-removal test, not a lethality test, so it does not belong in implant loads and does not replace biological monitoring. It is also repeated after repairs, but that is in addition to, not instead of, the daily requirement.AAMI ST79

A Bowie-Dick test sheet comes out of the sterilizer with a pale, uneven center and darker edges. What does this indicate and what should be done?

• a.Excessive steam pressure; reduce the set point and continue processing
• b.A normal result caused by the density of the test pack; the sterilizer may be used
• c.Incomplete air removal; the sterilizer should not be used for patient loads until the problem is corrected and a passing test is obtained✓
• d.A failed biological indicator; quarantine all implants processed that week

Uneven or lighter color change, especially in the center, means residual air remained in the pack and steam did not penetrate uniformly, which points to an air leak, a faulty vacuum pump, or a plugged drain. The sterilizer must be taken out of service for patient loads until the cause is found and a passing test is achieved. A non-uniform result is never normal, and the Bowie-Dick test measures air removal rather than pressure or microbial kill.AAMI ST79

After a tray fails its internal chemical indicator, the supervisor reviews the fundamentals with the team. Which four parameters must all be satisfied for steam sterilization to be effective?

• a.Time, temperature, moisture in the form of saturated steam, and direct contact with all surfaces✓
• b.Detergent, water quality, temperature, and packaging material
• c.Vacuum depth, drying time, cooling time, and package integrity
• d.Pressure, humidity, load weight, and cycle number

Steam sterilization depends on saturated steam reaching every surface at the required temperature for the required time, which is why cleaning, correct packaging, and proper loading matter so much. Pressure is only the means of achieving the temperature, not an independent parameter. Drying, cooling, and cleaning variables affect the outcome and package integrity but are not the four critical parameters of the sterilization process itself.AAMI ST79

Why is saturated steam, rather than superheated or wet steam, required for steam sterilization?

• a.Only saturated steam can pass through a sterilization wrapper
• b.Wet steam carries more heat energy and therefore sterilizes faster
• c.Saturated steam gives up its latent heat on contact with cooler surfaces, and both superheat and excess moisture disrupt that heat transfer✓
• d.Superheated steam is too cold to kill spores

Sterilization depends on condensation, which releases latent heat directly onto the item surface, and saturated steam near 97 percent dryness delivers that transfer efficiently. Superheated steam behaves like hot dry air and requires far longer exposure times, while wet steam carries excess water that causes wet packs and reduced penetration. Steam of any quality can physically pass through a wrapper, so that is not the distinguishing factor.AAMI ST79

Peel pouches are being loaded onto a sterilizer shelf. What is the correct placement?

• a.Stacked flat, plastic side up, so condensate runs off the film
• b.Laid flat and overlapping to maximize the number of pouches per shelf
• c.Positioned on edge in a rack, paper surface facing the plastic surface of the next pouch✓
• d.Stacked flat, paper side up, no more than ten deep

Placing pouches on edge with paper facing plastic lets steam enter through the porous paper and lets condensate drain away, which also improves drying. Stacking pouches flat traps air and moisture between them and blocks the porous side. Overlapping pouches likewise prevents steam contact and is a common cause of wet packs and failed indicators.AAMI ST79

A mixed load contains wrapped metal basin sets and textile packs. How should the load be arranged?

• a.Place metal and basin items on the lower shelves and textile packs on the upper shelves✓
• b.Place all items on a single shelf so the load remains compact
• c.Alternate metal and textile items on every shelf for even heat distribution
• d.Place textile packs on the bottom so metal weight does not crush them

Condensate forms on and drips from metal items, so putting them low keeps that moisture off absorbent textile packs and prevents wet packs. Placing textiles beneath metal is the classic cause of soaked wrappers. Alternating or compacting the load restricts steam circulation and creates cold spots, and items should never be packed tightly against each other or the chamber walls.AAMI ST79

A tray is removed from the sterilizer and the outer wrapper feels damp to the touch. What is the correct action?

• a.Set the tray aside until the moisture evaporates, then send it to storage
• b.Wipe the wrapper dry with a clean lint-free towel and release the tray
• c.Place the tray back in the sterilizer for an additional drying cycle and then release it
• d.Consider the package contaminated, do not use or store it, and reprocess the contents after investigating the cause✓

Moisture provides a wicking pathway for microorganisms from the outer surface to the contents, so a wet pack is considered contaminated regardless of whether the cycle parameters were met. The contents must be rewrapped and reprocessed, and the cause must be investigated. Air drying, wiping, or re-running only the drying phase does not restore sterility to a package that has already wicked.AAMI ST79

Wet packs are appearing intermittently across several loads. Which of the following is the least likely cause?

• a.Using a dynamic-air-removal cycle instead of a gravity cycle✓
• b.Poor steam quality with excess moisture in the supply line
• c.Overloading the chamber or packing items too densely
• d.Insufficient drying time or opening the door too early

Dynamic-air-removal cycles generally dry better than gravity cycles because the post-cycle vacuum helps pull moisture out, so cycle type is not a likely cause of wet packs. Overloading, dense packing, short drying times, premature door opening, clogged drains, faulty steam traps, and wet incoming steam are all recognized contributors. Cooling loads on a cold metal surface or in a drafty area also produces condensation.AAMI ST79

After a steam cycle finishes and the load is removed, how should the load be handled?

• a.Unloaded and immediately handled by staff wearing clean gloves
• b.Left undisturbed on the cart in a low-traffic, draft-free area until fully cool, typically 30 minutes or longer, before it is touched or moved✓
• c.Transferred immediately to sterile storage to protect it from room air
• d.Placed on a solid countertop and covered with a clean towel while it cools

Hot packages are vulnerable because handling them can drive condensation and contamination through the packaging, so the load is left to cool on the cart away from vents, drafts, and traffic. Cooling times of 30 minutes to an hour or more are common depending on load density. Placing hot items on a cold solid surface or covering them traps condensate, and gloves do not protect a package that is still hot and damp.AAMI ST79

Immediate-use steam sterilization (IUSS) is requested for a single dropped instrument during a case. Which statement is correct?

• a.IUSS eliminates the need for physical, chemical, and biological monitoring
• b.The item must still be thoroughly cleaned and decontaminated before it is placed in the sterilizer✓
• c.The item may be flash sterilized unwrapped and stored for later use if kept covered
• d.Cleaning may be abbreviated because the exposure temperature is higher

IUSS shortens the packaging and drying steps, not the cleaning step, and a device that is not properly cleaned cannot be sterilized by any cycle. Items processed by IUSS are transported for immediate use and are not stored for later cases. Physical monitors and chemical indicators are used with every IUSS cycle, and the sterilizer is monitored biologically at least daily or weekly per policy.AAMI ST79

Which practice regarding IUSS and implants is correct?

• a.Implants may be processed by IUSS if a Class 1 process indicator is placed on the tray
• b.Implants may be routinely processed by IUSS as long as the case is urgent
• c.IUSS of implants should be avoided; if unavoidable in a documented emergency, a rapid-readout biological indicator with a Class 5 integrating indicator is run and the event is documented✓
• d.Implants processed by IUSS require no biological monitoring because the cycle is unwrapped

Because a failed implant sterilization carries severe patient consequences, implants should be sterilized in a full terminal cycle and quarantined until the biological indicator result is known. In a documented emergency, IUSS may be used with a process challenge device containing a rapid-readout biological indicator and a Class 5 integrating indicator, and the exception must be recorded. Convenience or urgency alone does not justify the practice, and an external process indicator only shows exposure.AAMI ST79

A typical IUSS gravity cycle for nonporous metal instruments only is 270 degrees F (132 degrees C) for 3 minutes. What changes when the item is porous, cannulated, or has a lumen?

• a.The cycle is unchanged because IUSS parameters are fixed
• b.The item cannot be sterilized by steam under any circumstance
• c.A longer exposure, commonly 10 minutes in a gravity cycle, is required per the device manufacturer instructions✓
• d.The temperature is lowered to 250 degrees F and the time stays at 3 minutes

Porous items, lumens, and complex devices are harder for steam to penetrate, so validated IUSS parameters extend the exposure time, commonly to 10 minutes in a gravity cycle. The device manufacturer written instructions for use always define the required cycle. Lowering the temperature reduces lethality, IUSS parameters are not fixed across device types, and most such devices are perfectly steam compatible.AAMI ST79

A surgeon sends a heat-sensitive device with a long narrow lumen and asks whether it can be processed with ethylene oxide. Which statement describes ethylene oxide sterilization?

• a.A dry heat method used for oils, powders, and petroleum-based products
• b.A liquid immersion method used at the point of use for endoscopes
• c.A low-temperature gas method used for heat-sensitive and moisture-sensitive devices, including many long or narrow lumens✓
• d.A high-temperature method used as the fastest option for routine metal instruments

Ethylene oxide sterilizes at low temperature and penetrates well, which makes it valuable for delicate electronics, plastics, and devices with long narrow lumens that other low-temperature methods cannot handle. Its drawbacks are a long total cycle including mandatory aeration and significant worker safety and environmental controls. Dry heat is the method used for oils and powders, and liquid chemical sterilants are the point-of-use immersion option.AAMI ST79

Why must every ethylene oxide load undergo an aeration phase before items are released?

• a.Residual ethylene oxide absorbed into plastics and rubber is toxic and must be driven off to protect patients and staff✓
• b.Aeration is required only for loads that contain implants
• c.Aeration completes the microbial kill that the exposure phase started
• d.Aeration restores the humidity that was removed during the cycle

Ethylene oxide is a recognized carcinogen and irritant that is absorbed by polymers, so mechanical aeration at elevated temperature is required to reduce residuals to safe levels before handling or patient contact. Aeration times of about 8 to 12 hours or more are typical and are set by the device and sterilizer manufacturers. The kill occurs during exposure, not aeration, and the requirement applies to every load regardless of contents.OSHA

A tray wrapped in a cellulose-based (paper) wrapper is about to be loaded into a hydrogen peroxide gas plasma sterilizer. What is the problem?

• a.Cellulose reacts with hydrogen peroxide to form a toxic residue on instruments
• b.Cellulose absorbs hydrogen peroxide and will cause the cycle to abort or fail, so only nonwoven polypropylene wrap and compatible trays may be used✓
• c.Cellulose wrap is acceptable if a second wrapper is applied over it
• d.Cellulose wrap melts at the operating temperature of the sterilizer

Hydrogen peroxide is readily absorbed by cellulose materials such as paper, linen, and cotton, which strips sterilant from the chamber and causes cycle cancellation, so only polypropylene wrap, compatible pouches, and approved containers are used. The issue is absorption, not toxic residue formation or melting, since the process runs at low temperature. Adding a second cellulose layer makes the absorption problem worse.AAMI ST79

What are the byproducts of a hydrogen peroxide gas plasma sterilization cycle, and what does this mean operationally?

• a.Formaldehyde and methanol, which require a chemical scrubber
• b.Ethylene glycol and chlorohydrin, which require a long aeration phase
• c.Water vapor and oxygen, so no aeration period is required and items can be used immediately after the cycle✓
• d.Ozone and nitrogen, which require ventilation of the room for one hour

Hydrogen peroxide breaks down into water and oxygen, so there is no toxic residual and loads are available for immediate use, which is a major advantage over ethylene oxide. Ethylene glycol and ethylene chlorohydrin are ethylene oxide byproducts that drive its aeration requirement. Formaldehyde and ozone are separate sterilization agents, not plasma byproducts.AAMI ST79

An ozone sterilization system is being introduced. Which statement about ozone sterilization is accurate?

• a.Ozone is generated on demand from oxygen and water, sterilizes at low temperature, and reverts to oxygen with no toxic residue✓
• b.Ozone is generated from ethylene oxide and requires the same aeration as EO
• c.Ozone sterilizes at 270 degrees F and can replace steam for textile packs
• d.Ozone is used primarily for oils, powders, and anhydrous materials

Ozone sterilizers create the sterilant on site from medical-grade oxygen and water, which removes the need for stored chemical cartridges, and the ozone converts back to oxygen at the end of the cycle. It is a low-temperature method for heat-sensitive and moisture-sensitive devices, not a steam substitute for textiles. Dry heat, not ozone, is the method for oils and powders, and ozone is unrelated to ethylene oxide.AAMI ST79

A department is deciding which sterilization method to use for a heat-stable stainless steel instrument set. Which method should be selected and why?

• a.Steam, because it is the safest, fastest, least expensive, and most reliable method for heat-tolerant and moisture-tolerant items✓
• b.Dry heat, because it does not corrode stainless steel
• c.Hydrogen peroxide gas plasma, because it is the shortest cycle available
• d.Ethylene oxide, because it penetrates box locks better than steam

Whenever a device tolerates heat and moisture, steam is the preferred method because it is nontoxic, inexpensive, well validated, and rapid. Low-temperature methods are reserved for devices that cannot survive steam, and each carries material restrictions, cost, and in the case of ethylene oxide, worker safety burdens. Dry heat requires very long exposure times and is limited to a narrow set of materials.AAMI ST79

A technician receives a jar of petroleum-based lubricant and a container of powder that must be sterilized. Which method applies, and what are representative parameters?

• a.Rigid containers with filters, at 270 degrees F for 4 minutes
• b.Oils, petroleum-based lubricants, and powders, at approximately 320 degrees F for 2 hours or 340 degrees F for 1 hour✓
• c.Textile packs, at 275 degrees F for 3 minutes
• d.Flexible endoscopes, at 250 degrees F for 30 minutes

Dry heat is used for anhydrous materials that steam cannot penetrate, such as oils, ointments, and powders, and it needs long exposure at high temperature because heat transfer without moisture is inefficient. Flexible endoscopes are heat sensitive and are high-level disinfected or low-temperature sterilized. The 270 and 275 degrees F short cycles listed are steam parameters, not dry heat.AAMI ST79