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Sterile Processing Technician Exam

Decontamination Practice Questions

39 practice questions with detailed explanations — aligned to the Sterile Processing Technician Exam.

  1. Q1.What is the first step in the decontamination process?

    A.Manual cleaning
    B.Point-of-use treatment
    C.Sorting
    D.Disinfection
    BPoint-of-use treatment

    Explanation: Decontamination begins at the point-of-use (in the OR) to prevent blood/soil from drying on instruments. This makes subsequent cleaning steps effective.

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  2. Q2.The ideal temperature for enzymatic cleaners is typically:

    A.Above 140°F (60°C)
    B.Below 100°F (38°C)
    C.Between 109°F - 140°F (43°C - 60°C)
    D.Boiling
    CBetween 109°F - 140°F (43°C - 60°C)

    Explanation: Enzymes are proteins that work best at specific warm temperatures. Too hot (>140°F) kills the enzymes; too cold renders them sluggish. Always check manufacturer IFUs.

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  3. Q3.Cavitation is the cleaning mechanism used in:

    A.Washer-disinfectors
    B.Ultrasonic cleaners
    C.Cart washers
    D.Steam sterilizers
    BUltrasonic cleaners

    Explanation: Ultrasonic cleaners use sound waves to create microscopic bubbles that implode (cavitation), pulling soil off surfaces and crevices.

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  4. Q4.Which type of water is recommended for the final rinse of critical medical devices?

    A.Tap water
    B.Critical water (Deionized/Distilled/Reverse Osmosis)
    C.Softened water
    D.Utility water
    BCritical water (Deionized/Distilled/Reverse Osmosis)

    Explanation: Final rinses require water free of minerals and impurities (Critical Water) to prevent staining, corrosion, and pyrogen contamination.

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  5. Q5.When manually cleaning a device, the brushing motion should be performed:

    A.Above the water line to see clearly
    B.Under the water line to prevent aerosolization
    C.Vigorously with a wire brush
    D.Only on the exterior surfaces
    BUnder the water line to prevent aerosolization

    Explanation: Brushing under the water surface prevents aerosols containing pathogens from becoming airborne and contaminating the technician.

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  6. Q6.A washer-disinfector uses which process to achieve thermal disinfection?

    A.Chemical exposure
    B.Impingement
    C.Hot water rinse (typically 180°F - 203°F)
    D.Ultrasonic waves
    CHot water rinse (typically 180°F - 203°F)

    Explanation: Thermal disinfection in automated washers relies on sustaining a high temperature rinse for a specific time to kill vegetative microorganisms.

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  7. Q7.Items with lumens (channels) must be:

    A.Soaked only
    B.Brushed with a properly sized brush and flushed
    C.Processed in the ultrasonic only
    D.Sterilized without cleaning
    BBrushed with a properly sized brush and flushed

    Explanation: Soaking isn't enough. Friction (brushing) is required to remove soil inside the lumen, followed by flushing to clear debris.

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  8. Q8.The pH of a detergent used for anodized aluminum containers (rigid containers) should be:

    A.High alkaline
    B.Neutral (pH 7)
    C.Acidic
    D.Low alkaline
    BNeutral (pH 7)

    Explanation: Anodized aluminum is damaged by high/low pH. Neutral pH detergents are required to prevent corrosion/pitting of the protective layer.

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  9. Q9.Proper airflow in the decontamination area should be:

    A.Positive pressure
    B.Negative pressure
    C.Neutral pressure
    D.It doesn't matter
    BNegative pressure

    Explanation: Negative pressure ensures that air flows *into* the decon area from clean areas and is exhausted outside, preventing contaminants from drifting into clean prep areas.

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  10. Q10.TASS (Toxic Anterior Segment Syndrome) is an acute inflammation of the eye caused by:

    A.Bacteria
    B.Inadequate removal of detergent or chemical residues from ophthalmic instruments
    C.Viral infection
    D.Patient allergies
    BInadequate removal of detergent or chemical residues from ophthalmic instruments

    Explanation: TASS is a sterile inflammatory reaction caused by toxic residues (like detergents, endotoxins, or enzymes) left on eye instruments. Thorough rinsing with critical water is essential.

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  11. Q11.Before placing instruments into an ultrasonic cleaner, they must be:

    A.Sterilized
    B.Grossly cleaned of visible soil
    C.Dry
    D.Lubricated
    BGrossly cleaned of visible soil

    Explanation: Ultrasonic cleaners are for fine cleaning. Gross soil inhibits cavitation and contaminates the bath quickly. Pre-cleaning is mandatory.

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  12. Q12.Descaling is the process of:

    A.Removing instruments from a tray
    B.Removing scale (mineral deposits) from the chamber of a washer or sterilizer
    C.Checking weight
    D.Lubricating instruments
    BRemoving scale (mineral deposits) from the chamber of a washer or sterilizer

    Explanation: Hard water leaves chalky mineral deposits (scale) on equipment walls. Descaling agents (acidic) remove this buildup to maintain efficiency.

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  13. Q13.Which agency regulates disinfectants and sterilants used on non-living surfaces?

    A.FDA
    B.EPA (Environmental Protection Agency)
    C.OSHA
    D.CDC
    BEPA (Environmental Protection Agency)

    Explanation: The EPA regulates surface disinfectants and liquid chemical sterilants (as pesticides). The FDA regulates high-level disinfectants used on medical devices.

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  14. Q14.Personal Protective Equipment (PPE) for the decontamination area includes:

    A.Lab coat only
    B.Gloves, fluid-resistant gown, eye protection, face mask/shield, and shoe covers
    C.Sterile gloves and gown
    D.Street clothes
    BGloves, fluid-resistant gown, eye protection, face mask/shield, and shoe covers

    Explanation: Full PPE is required to protect against splashes and biohazards. Heavy-duty utility gloves are preferred over exam gloves.

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  15. Q15.A 'High-Level Disinfectant' (HLD) kills:

    A.All microorganisms including high numbers of bacterial spores
    B.All vegetative bacteria, viruses, fungi, and mycobacteria, but not necessarily high numbers of spores
    C.Only bacteria
    D.Only viruses
    BAll vegetative bacteria, viruses, fungi, and mycobacteria, but not necessarily high numbers of spores

    Explanation: HLD kills almost everything (TB, viruses, fungi) but cannot guarantee the kill of high numbers of spores (that requires sterilization).

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  16. Q16.The minimum effective concentration (MEC) of a high-level disinfectant must be tested:

    A.Once a week
    B.Once a day
    C.Before each use (or load)
    D.When the bottle is opened
    CBefore each use (or load)

    Explanation: HLD solutions (like Glutaraldehyde or OPA) degrade over time. You must dip a test strip before *every* use to ensure potency.

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  17. Q17.According to the Spaulding Classification, 'Semi-critical' items require at least:

    A.Cleaning only
    B.Low-level disinfection
    C.High-level disinfection
    D.Sterilization
    CHigh-level disinfection

    Explanation: Semi-critical items touch mucous membranes (e.g., endoscopes, anesthesia blades) and require High-Level Disinfection. Critical items (enter sterile tissue) require sterilization.

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  18. Q18.Why must instruments be disassembled before cleaning?

    A.To count the parts
    B.To ensure cleaning agents contact all surfaces
    C.To make them fit in the tray
    D.It is not required
    BTo ensure cleaning agents contact all surfaces

    Explanation: Bioburden hides under movable parts. Disassembly ensures detergent and water reach every surface.

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  19. Q19.Ortho-phthalaldehyde (OPA) is a common:

    A.Enzymatic cleaner
    B.High-level disinfectant
    C.Sterilant gas
    D.Lubricant
    BHigh-level disinfectant

    Explanation: OPA is a widely used liquid high-level disinfectant for flexible endoscopes. It is a safer alternative to glutaraldehyde.

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  20. Q20.If a rigid container is returned to decontamination with the filter still in place:

    A.The filter can be reused if clean
    B.The filter must be removed and discarded, and the retention plate cleaned
    C.The container can be washed with the filter
    D.Leave it for the assembly side
    BThe filter must be removed and discarded, and the retention plate cleaned

    Explanation: Disposable filters are single-use. They must be removed in decon to allow proper cleaning of the lid and retention plate.

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  21. Q21.When loading a mechanical washer, instruments should be placed:

    A.Stacked on top of each other
    B.In the closed position
    C.In the open/unlocked position
    D.In peel pouches
    CIn the open/unlocked position

    Explanation: Box locks and ratchets must be open to allow spray action to reach the hinge areas and jaws.

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  22. Q22.The 'hollow' cavitation test used for ultrasonic cleaners involves:

    A.A ceramic disc
    B.Aluminum foil
    C.A TOSI test
    D.A biological indicator
    BAluminum foil

    Explanation: The aluminum foil test detects uneven cavitation. (Note: Newer commercial tests like SonoCheck are also used, but foil is the classic textbook answer for verifying cavitation energy distribution).

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  23. Q23.Prions (which cause CJD) are uniquely resistant to:

    A.Standard cleaning
    B.Standard sterilization cycles (normal steam/EtO)
    C.High-level disinfection
    D.All of the above
    DAll of the above

    Explanation: Prions are misfolded proteins that are incredibly resistant. They require extended sterilization cycles (e.g., 18 min at 273°F or 1 hour at 250°F) and specific cleaning protocols.

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  24. Q24.Which detergent is best for removing stubborn organic soils like dried blood?

    A.Acidic detergent
    B.Enzymatic detergent (Protease)
    C.High alkaline detergent
    D.Neutral detergent
    BEnzymatic detergent (Protease)

    Explanation: Protease enzymes specifically break down proteins (blood/tissue). Lipase breaks down fats.

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  25. Q25.Transporting contaminated items to the decontamination area requires:

    A.Carrying them in hand
    B.A closed, leak-proof container marked with a biohazard label
    C.An open wire cart
    D.A clear plastic bag
    BA closed, leak-proof container marked with a biohazard label

    Explanation: OSHA requires biohazardous materials to be contained in leak-proof, labeled containers to protect staff and the environment during transport.

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  26. Q26.Power equipment (drills, saws) should generally be:

    A.Immersed in water
    B.Cleaned manually (wiped down) and never immersed
    C.Processed in the ultrasonic
    D.Put in the washer-disinfector
    BCleaned manually (wiped down) and never immersed

    Explanation: Immersion allows water to enter the motor housing, destroying the mechanism. Follow IFU carefully—usually manual wipe-down.

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  27. Q27.Biofilms are:

    A.A type of soap
    B.A protective slime layer created by colonies of bacteria that resists cleaning and disinfection
    C.A sterile barrier
    D.A lubricant
    BA protective slime layer created by colonies of bacteria that resists cleaning and disinfection

    Explanation: Biofilms form when bacteria attach to a surface and secrete a matrix (slime). They are very hard to remove and shield bacteria from chemicals.

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  28. Q28.Robotic instruments (like DaVinci) typically require:

    A.Less cleaning time
    B.Standard washing
    C.Complex, validated cleaning protocols involving specific flushing and ultrasonic processing
    D.No cleaning
    CComplex, validated cleaning protocols involving specific flushing and ultrasonic processing

    Explanation: Robotic arms have complex cables and pulleys. They require very specific, time-intensive manual and automated cleaning steps.

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  29. Q29.The temperature of the decontamination area should be maintained between:

    A.60°F - 65°F (16°C - 18°C)
    B.68°F - 73°F (20°C - 23°C)
    C.75°F - 80°F (24°C - 27°C)
    D.Whatever is comfortable
    A60°F - 65°F (16°C - 18°C)

    Explanation: Decon should be cooler (60-65°F) to inhibit bacterial growth and keep staff comfortable while wearing hot PPE.

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  30. Q30.If instruments arrive from the OR with saline on them, what will likely happen?

    A.They will be cleaner
    B.Pitting and corrosion will occur
    C.They will be sterile
    D.Nothing
    BPitting and corrosion will occur

    Explanation: Saline is salt water. Salt causes rapid corrosion (rust/pitting) on stainless steel. OR staff should use sterile water, not saline, to keep items moist.

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  31. Q31.Degassing an ultrasonic cleaner is done to:

    A.Remove dissolved gases from the water to improve cavitation
    B.Remove soil
    C.Heat the water
    D.Cool the water
    ARemove dissolved gases from the water to improve cavitation

    Explanation: Excess gas bubbles cushion the cavitation implosions, reducing cleaning power. Running the unit empty for a cycle degasses the water.

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  32. Q32.Glutaraldehyde usually requires a soak time of ____ for high-level disinfection at 20°C.

    A.5 minutes
    B.45-90 minutes
    C.10 hours
    D.24 hours
    B45-90 minutes

    Explanation: For HLD, Glutaraldehyde typically requires 45-90 mins (depending on formulation). For Sterilization, it requires 10 hours.

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  33. Q33.Phenolics are environmental disinfectants that should generally NOT be used on:

    A.Floors
    B.Walls
    C.Surgical instruments or items that contact skin/infants
    D.Trash cans
    CSurgical instruments or items that contact skin/infants

    Explanation: Phenolics leave a residue that can irritate skin and is toxic to infants (depigmentation). They are for environmental surfaces only.

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  34. Q34.The final step in manual cleaning is:

    A.Brushing
    B.Enzymatic soak
    C.Thorough rinsing with critical water
    D.Drying
    CThorough rinsing with critical water

    Explanation: Rinsing removes the detergent and loosened soil. Critical water prevents recontamination/staining. (Drying follows, but rinsing is the final 'cleaning' step action).

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  35. Q35.Loaner instruments should be:

    A.Sent straight to the OR
    B.Sterilized immediately
    C.Logged in, inspected, and completely reprocessed (cleaned and sterilized) by the facility
    D.Wiped down only
    CLogged in, inspected, and completely reprocessed (cleaned and sterilized) by the facility

    Explanation: You cannot trust outside processing. Loaners must be treated as contaminated and go through the full decontamination cycle at the receiving facility.

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  36. Q36.When cleaning a Kerrison Rongeur, the most critical step often missed is:

    A.Lubrication
    B.Testing sharpness
    C.Disassembling the instrument or opening the slide mechanism to clean the track
    D.Soaking it
    CDisassembling the instrument or opening the slide mechanism to clean the track

    Explanation: Kerrisons have a sliding mechanism that traps bone and tissue. If not disassembled or opened fully during cleaning, bioburden remains trapped inside, leading to sterilization failure.

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  37. Q37.A Loaner Set arrives at 2:00 PM for a 3:00 PM case. The manufacturer IFU requires an 8-minute steam cycle. The hospital's policy allows IUSS. What is the BEST decision?

    A.Flash (IUSS) the tray to get it there on time
    B.Inform the OR that the case must be delayed to allow for proper reprocessing
    C.Wipe it down with alcohol and send it up
    D.Use the hospital's own instruments instead
    BInform the OR that the case must be delayed to allow for proper reprocessing

    Explanation: Patient safety comes first. Loaner trays must be fully decontaminated and sterilized. 1 hour is insufficient for proper processing (soak, clean, pack, sterilize, cool). Pressure to flash sterilize due to late delivery should be resisted.

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  38. Q38.Which water quality issue creates a 'rainbow' effect or stain on stainless steel instruments?

    A.High pH
    B.Silicates
    C.Chloride
    D.Iron
    BSilicates

    Explanation: Excessive silicates in the water supply typically cause blue/rainbow discoloration on instruments.

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  39. Q39.A 'TASS' outbreak in the ophthalmology department would trigger an audit of:

    A.The steam quality
    B.The cleaning and rinsing protocols for eye instruments (water quality, detergent residue)
    C.The air handling system
    D.The peel pouches
    BThe cleaning and rinsing protocols for eye instruments (water quality, detergent residue)

    Explanation: Toxic Anterior Segment Syndrome (TASS) is caused by residues (detergents, endotoxins) left on eye instruments. The audit would focus on water quality (critical water) and rinsing steps.

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