Sterilization and Disinfection

Which of the following statements regarding the sterilization of basin sets is TRUE? (A) Basins must be separated by a porous material if they are nested (B) Sponges and linen may be packaged inside the basin to be sterilized (C) Basins are placed flat in the autoclave (D) Basins must always be placed on the top shelf of the autoclave in a combined load

(A) Basins and solid utensils must be separated by a porous material if they are nested, to permit permeation of steam around all surfaces, and condensation of steam from the inside during sterilization. Sponges or linen are not packaged in basins.

Bioburden refers to: (A) the degree of microbial contamination (B) a hospital acquired infection(C) a chemical agent(D) high-level disinfectant

(A) Bioburden is the number and the type of live bacterial colonies on the surface before it is sterilized.

According to the Spaulding system, what risk is assigned to sterile body tissue including the vascular system? (A) Critical(B) Semicritical(C) Noncritical(D) Intermediately critical

(A) Critical risk is assigned to sterile body tissues including the vascular system.

Ethylene oxide destroys cells by: (A) interfering with the normal metabolism of the protein and reproductive processes (B) coagulating cell protein(C) converting ions to thermal and chemical energy causing cell death(D) shrinking the cell

(A) EO or ETO is a chemical agent that kills microorganisms, including spores. It interferes with the normal metabolism of protein and reproductive processes, resulting in cell death.

All are environmental disinfectants used for low-level disinfection and terminal decontamination EXCEPT: (A) glutaraldehyde(B) hypochlorite(C) quaternary ammonium compound (D) alcohol

(A) Environmental disinfectants that are used for routine low-level disinfection and terminal decontamination include phenolics, quats, hypochlorites, and alcohol. Gluteraldehyde is a high-level disinfectant known as Cidex commonly used on instruments.

The amount of pressure necessary in a steam sterilizer set at 250°F is: (A) 15-17 lb (B) 20-22 lb (C) 22-25 lb (D) 25-27 lb

(A) Fifteen to seventeen pounds of pressure is necessary in the steam sterilizer set at 250°F. It is 27 psi if set at 270°F.

What is the shelf life of Cidex? (A) 14 days (B) 7 days (C) 1 month (D) Indefinite

(A) Gluteraldehyde must be renewed after 14 days because it becomes ineffective after that time.

Gravity displacement, steam sterilizers operate on the principle that: (A) air is heavier than steam(B) air and steam have equal weight (C) steam is heavier than air(D) water is heavier than air

(A) Gravity displacement steam sterilizers operate on the principle that air is heavier than steam. Steam is forced into the inner chamber. Any air in the inner chamber blocks the passage of pressurized steam and prevents sterilization.

Hydrogen peroxide plasma sterilization utilizes: (A) a cloud or glow of pink plasma sterilization utilizes: (B) a chamber much like microwaves(C) using a hydrogen peroxide solution(D) All of the above

(A) Hydrogen peroxide plasma sterilization utilizes a loud or glow of pink plasma covering the items to be sterilized.

For ETO sterilization, how long must instruments remain in the aerator being operated at 140°F? (A) 8 hours (B) 6 hours (C) 4 hours (D) 2 hours

(A) Instruments must remain in the aerator cycle of the ETO at 140°F degrees for 8 hours.

What method of sterilization is used on objects that cannot tolerate heat, moisture, and the presence of steam sterilization? (A) Gravity displacement (B) ETO(C) Hydrogen peroxide (D) Cidex

(B) ETO is used to sterilize objects that cannot tolerate heat, moisture, and the pressure of steam sterilization.

Which of the following is essential when using shelf of the autoclave in a combined load-activated glutaraldehyde for sterilization? (A) Items must be rinsed thoroughly in sterile water before use(B) The solution must be heated in order to be effective(C) The items must be thoroughly moistened before placement in solution (D) The item must be air dried before use

(A) Items must be thoroughly rinsed before use. Solution is reusable for the time set by the manufacturer. Items must be clean and dry before submersion.

To be sterilized effectively, a linen pack must not weigh more than: (A) 12 lb (B) 14 lb (C) 16 lb (D) 18 lb

(A) Linen packs must not weigh more than 12 lb. Linen must be freshly laundered. Items must be fanfolded or loosely rolled.

What is the immunity referred to when you are exposed to the disease and as a result you become immune: (A) naturally acquired active immunity (B) artificially acquired active immunity (C) artificially acquired passive immunity (D) naturally acquired passive immunity

(A) Naturally acquired active immunity is when you are exposed to the disease and as a result become immune. Artificially acquired active immunity is when you receive a vaccine and become immune. Artificially acquired passive immunity is when you receive immunization such as gamma globulin. It is a short-term immunization. Naturally acquired passive immunity occurs during pregnancy when a pregnant woman passes the antibodies to her fetus through the blood stream.

A 30-minute single-use sterilization system useful for endoscopes is: (A) STERIS(B) ETO(C) steam under pressure (D) cold sterilization

(A) Peracitic acid is used in a machine (STERIS) that heats the sterilant and can be used for endoscopes. The cycle takes 30 minutes, and the sterilant can only be used for a single sterilization cycle, thus is more expensive than other methods.

Positive assurance that sterilization conditions have been achieved can only be obtained through: (A) biological control test (B) heat-sensitive tape (C) color change monitor (D) mechanical indicator

(A) Positive assurance that sterile conditions have been achieved by either steam, ethylene oxide, or dry heat sterilization can be obtained only through a biological control test. These should be done at least weekly. The most dependable is a preparation of living spores resistant to the sterilizing agent.

The chemical name for common household bleach is: (A) sodium hypochlorite(B) quaternary ammonium compounds (C) petroleum products(D) hydrogen peroxide

(A) Sodium hypochlorite is the chemical name for household bleach.

Which of the following kills bacterial spores? (A) Sterilant (B) Germicide (C) Antiseptic (D) Fungicide

(A) Spores are not killed unless an item is sterilized.

The bacterial spore used in the biological indicator for steam sterilization is Geobacillus stearothermophilus when killed within 60 minutes, the enzyme in the biological indicator will turn what color: (A) fluorescent yellow (B) red(C) blue(D) no specific color

(A) The enzyme in the biological indicator will turn fluorescent yellow.

Why is ethylene oxide diluted with an inert gas? (A) It increases its effective sterilization (B) It adds convenience and speed(C) It adds humidity(D) It helps with aeration

(A) When blended with inert gas, it produces effective sterilization by destroying DNA and the protein structure of microorganisms

What chemical system uses peracetic acid as the sterilant? (A) Ozone gas sterilization (B) STERIS(C) Sterrad(D) Vapor phase sterilizer

(B) A proprietary (STERIS) chemical formulation of peracetic acid, hydrogen peroxide, and water causes cell death by inactivating the cell systems.

What is the function of an aerator in EO sterilization? (A) It is used to aerate items before sterilization(B) It is a separate unit used to decrease the aeration time(C) It is the last cycle in the EO sterilizer, which helps exhaust the gas and add air (D) It adds air to the cycle, which is essential for obtaining item sterility

(B) Aeration following EO sterilization can be accomplished at room temperature; however, aeration of exposed items at an elevated temperature (in an aerator) enhances the dissipation rate of absorbed gases, resulting in faster removal. The aerator is a separate unit.

An obligatory parasite is: (A) a type of prion(B) a type of microorganism that depends on living tissue to survive(C) a type of microorganism that depends on dead tissue to survive facultative parasite (D) All of the above

(B) An obligatory parasite is a type of microorganism that depends on living tissue to survive.

The lumen of a tubing undergoing ethylene oxide (EO) sterilization is: (A) well lubricated(B) dried thoroughly(C) prepared with a residual of distilled water (D) prepared with a NaCl flush

(B) Any tubing or other item with a lumen should be blown out with air to force dry before packaging, as water combines with EO gas to form a harmful acid, ethylene glycol.

What spore is used to test steam under pressure (steam sterilizer)? (A) Clostridium perfringens (B) Bacillus stearothermophilus (C) Treponema pallidum(D) Staphylococcus aureus

(B) B. stearothermophilus is the spore used to test steam under pressure sterilizers.

How should basins be positioned in the autoclave for sterilization? (A) Stacked on top of each other (B) On their sides(C) Upside down(D) Does not matter

(B) Basins, jars, cups, or other containers should be placed on their sides with the lid ajar so that air can flow out and steam can enter.

Why would gas sterilization be chosen over steam sterilization? (A) It is less expensive(B) It is less damaging to items (C) It is faster(D) It is more effective

(B) EO gas is an effective substitute for most items that cannot be sterilized by heat or that would be damaged by repeated exposure to heat. It is noncorrosive and does not damage items. It completely penetrates porous materials.

How long should the ETO biological indicator be incubated before the reading is recorded? (A) 24 hours (B) 48 hours (C) 12 hours (D) 3 hours

(B) ETO biological indicators should be incubated for 48 hours before reading.

ETO is mixed with carbon dioxide to: (A) increase antimicrobial effect(B) reduce flammability of ETO (C) reduce temperature requirement (D) increase microbial killing rate

(B) ETO is mixed with carbon dioxide to reduce the flammability of the ETO.

All are true of dry heat sterilization EXCEPT: (A) the indicator used for dry heat ovens are B. atrophaeus (B) it is used only in an emergency in the operating room (C) sterilization occurs in mechanical convection ovens (D) sterilization occurs in gravity convection ovens

(B) Heat sterilization is not only used in an emergency.

The minimum exposure time for unwrapped instruments in a flash sterilizer that is set at 270°F (132°C) is: (A) 2 minutes (B) 3 minutes (C) 5 minutes (D) 7 minutes

(B) In a flash (high speed pressure) sterilizer set at 270°F, the minimum exposure time is 3 minutes for unwrapped items. With this cycle, the entire time for starting, sterilizing, etc., is 6-7 minutes.

When placing tubing in an activated glutaraldehyde solution, one should: (A) use a shallow container(B) be certain that the interior of the tubing is completely filled (C) moisten it thoroughly before submersion(D) BothBandC

(B) Lumens of instruments or tubing must be completely filled with solution. All items should be placed in a container deep enough to completely immerse them. All items should be dry before immersion so that the solution is not diluted.

Most packaged sterilized equipment from a manufacturer such as sutures, sponges, and disposable drapes are sterilized by means of: (A) ETO(B) Cobalt 60 (ionizing radiation)(C) gravity displacement sterilizer(D) quaternary ammonium compounds

(B) Most equipment available that is packaged from the manufacturer has been sterilized by Cobalt 60 or ionizing radiation. This process is restricted to commercial use because of its expense.

Which is not a method of sterilization but is a heating process that destroys microorganisms at a temperature and exposure time but does not alter their chemical makeup: (A) decontamination (B) pasteurization(C) hydrogen peroxide plasma sterilization (D) ETO gas sterilization

(B) Pasteurization is a heating process that destroys microorganisms at a certain temperature and exposure time but does not alter their chemical makeup.

Personal protective equipment includes all EXCEPT: (A) goggles(B) surgical and/or patient care gloves (C) facemask(D) protective body clothing

(B) Personal protective equipment includes goggles, facemasks, and protective body clothing.

All are true regarding a prion EXCEPT: (A) Creutzfeldt-Jakob disease(B) they contain DNA/RNA(C) It is neither viral, bacterial, nor fungal(D) When performing surgery on a patient that is infected with a prion, we should use disposable instruments

(B) Prions do not contain DNA/RNA.

When using a high-level disinfectant, always: (A) submerge items while wet(B) rinse items with sterile distilled water before using (C) soak items in saline before using(D) add hot diluent to activated agent

(B) Scopes and all accessories that are soaked in activated glutaraldehyde are rinsed well in sterile distilled water to prevent tissue irritation from the solution.

"Slow exhaust" in a gravity displacement steam sterilizer is used for: (A) plastics(B) solutions (C) rubber(D) drape packs

(B) Solutions are sterilized alone on slow exhaust so solutions will not boil over and so caps will not blow off.

What is the test that is used to check for air trapped in the prevacuum sterilizer? (A) Biological indicator (B) Bowie-Dick test (C) Chemical indicator (D) Prevacuum test

(B) The Bowie-Dick test is used to check for air trapped in the prevacuum sterilizer. The biological indictor is the most effective indicator to prove sterility. A chemical indicator is tape used in the autoclave.

Instrumentation and equipment are processed according to their level of risk. This system is known as: (A) evidence-based practice (B) the Spaulding method (C) reprocessing(D) central monitoring

(B) The Spaulding system assigns a risk category that is specific to the regions of the body in which a device is to be used.

In a high-speed flash sterilizer, unwrapped instruments are exposed for a minimum of: (A) 1 minute (B) 3 minutes (C) 5 minutes (D) 10 minutes

(B) The minimum exposure time at 270°F with 27 psi is 3 minutes for unwrapped nonporous items.

The process called cavitation occurs in the: (A) moist heat sterilizer(B) ultrasonic cleaner(C) high-speed pressure sterilizer (D) washer-sterilizer

(B) The ultrasonic cleaner (which is not a sterilizer) utilizes ultrasonic energy and high-frequency sound waves. Instruments are cleaned by cavitation. In this process, tiny bubbles are generated by high- frequency sound waves. These bubbles generate minute vacuum areas that dislodge, dissolve, or disperse soil.

Activated glutaraldehyde is used to disinfect endoscopes for: (A) 5 minutes (B) 10 minutes (C) 20 minutes (D) 60 minutes

(C) A minimum of 20 minutes is used to kill vegetative bacteria, fungi, hepatitis B, and HIV. It is 45 minutes for tuberculocidal activity.

Personal protective equipment (PPE) includes all of the following EXCEPT: (A) protective eyewear(B) facemask(C) surgical and/or patient care gloves (D) full protective body suit or gown

(C) All staff members who work in the decontamination area must wear PPE in compliance with government regulations. Only gloves approved for contact with chemical disinfectants are used. Surgical gloves and patient care gloves are not permitted.

Gastrointestinal endoscopes are characterized _______ under the Spaulding sterilization system. (A) critical(B) noncritical(C) semicritical(D) scopes are not considered in the Spaulding system

(C) Gastrointestinal scopes come in contact with mucous membranes or nonintact skin. They are semicritical items.

All of the following statements regarding instrument sets are true EXCEPT: (A) instruments must be placed in perforated trays (B) heavy instruments are placed on the bottom (C) all instruments must be closed(D) all detachable parts must be disassembled

(C) Hinged instruments must be open with box locks unlocked to permit steam contact on all surfaces. All detachable parts should be disassembled.

To kill spores, an item must be immersed in a 2% aqueous solution of glutaraldehyde for: (A) 20 minutes (B) 2 hours (C) 10 hours (D) 24 hours

(C) Immersion in a 2% aqueous solution of activated, buffered alkaline glutaraldehyde is sporicidal (kills spores) within 10 hours. It is chosen for heat-sensitive items that cannot be steamed or if EO gas is unavailable or impractical.

In which procedure would the use of a high-level disinfectant be acceptable instrument preparation? (A) Suction lipectomy (B) Tracheotomy(C) Cystoscopy(D) Mediastinoscopy

(C) In cystoscopy, sterilization of instruments with steam or EO provides the greatest elimination of the risk of infection; however, it is not essential. High-level disinfection is recommended and provides reasonable assurance that items are safe to use.

A wrapped tray of instruments is sterilized in a gravity displacement sterilizer at 250°F for: (A) 10 minutes (B) 15 minutes (C) 30 minutes (D) 40 minutes

(C) Instruments wrapped as a set in double thickness wrappers are autoclaved at a setting of 250°F for 30 minutes.

What is the role of moisture in EO sterilization? (A) The items will dry out during the process if no humidity is added(B) The sterilizer will deteriorate from gas over a period of time if no moisture is added (C) Dried spores are resistant to the gas, so they must be hydrated (D) Moisture is not an essential element in gas sterilization

(C) Moisture is essential in gas sterilization. Desiccated or highly dried bacterial spores are resistant to EO gas; therefore, they must be hydrated in order for the gas to be effective.

______ is when different organisms exist and benefit from the other. ______ is when one organism benefits from the other and neither is harmed. _____ is when one organism benefits from the other and harms the host: 1. Parasitism 2. Mutualism 3. Commensalism (A) 1,2,3(B) 3,2,1(C) 2,3,1 (D) 1,3,2

(C) Mutualism, commensalism, and parasitism.

Chemical monitors are placed inside and outside of all packs to be sterilized. This monitor shows: (A) the item is sterile(B) proper packaging is achieved(C) the parameters such as heat and pressure have been reached (D) the proper time has been met

(C) Subjecting items to the process of sterilization does not ensure that the item is sterile, but only that the parameters such as heat and pressure have been met.

Instruments and equipment are processed according to their level of risk. This system is known as: (A) ETO sterilization(B) event related sterility(C) the Spaulding method(D) instrument cleaning and disinfection

(C) The Spaulding method is used to rate the level of risk when processing equipment.

To achieve 270°F, the required pressure is: (A) 15 psi (B) 20 psi (C) 27 psi (D) 40 psi

(C) The laws of physics tell us to raise the temperature of steam, we must also raise the pressure in the closed sterilization chamber, to achieve 270°F, and the required pressure is 27 psi.

Gluteraldehyde is a high-level disinfectant, that is, a sporicidal, a bacteriocidal, and a virocidal at a 2% concentration for _______, it is also a tuberculocidal. (A) 10 minutes (B) 15 minutes (C) 20 minutes (D) 40 minutes

(C) Two percent gluteraldehyde is a tuberculocidal when item is sterilized for 20 minutes.

The process of terminal decontamination follows every surgical case. Decontamination of the walls consists of: (A) cleaning all walls up to 3 ft (B) cleaning all walls up to 1 ft (C) spot clean where soiled (D) always clean with alcohol

(C) Walls, doors, surgical lights, and ceilings are spot cleaned if they are soiled with blood tissue or body fluids.

Bioterrorist agents include all EXCEPT: (A) anthrax(B) botulism(C) small pox(D) bubonic plague

(D) Anthrax, botulism, and small pox are bioterrorist agents.

The chemical agent used in gas sterilization is: (A) ethylene glycol(B) ethacrynate sodium (C) ethyl chloride(D) ethylene oxide

(D) Ethylene oxide gas is used to sterilize items that are either heat or moisture sensitive. It kills microorganisms, including spores, by interfering with the normal metabolism of protein and reproductive processes.

Sterility was previously measured by time but is now considered invalid. The principle now used is: (A) carefully checking sterile indicators (B) event-related sterility (C) terminal sterilization (D) BothBandC

(D) Event-related sterility or terminal sterilization is based on the principles that sterilized items are assumed sterile between uses unless environmental conditions or events interfere with the integrity of the package.

The commercial name for glutaraldehyde is: (A) peracetic acid (B) phenol(C) Quats(D) Cidex

(D) Glutaraldehyde, a high-level disinfectant is known commercially as Cidex.

Gravity displacement utilizes ________ to destroy microorganisms. (A) gas(B) radiation (C) gamma rays (D) steam

(D) Gravity displacement utilizes steam under pressure to effect moist heat sterilization.

The following statements regarding wrapping materials are true EXCEPT: (A) Disposable nonwoven wrappers are intended for one use only(B) You can use two 140 thread count per square inch(C) You can use one 280 thread count per square inch(D) Peel pouches can be used on all instruments including large heavy instruments and micro instruments

(D) Peel pouches are intended for light-weight instruments and devices.

The chemical sterilant used in the STERIS method of sterilizing is: (A) formaldehyde (B) Cidex(C) ethylene oxide (D) peracetic acid

(D) Peracetic acid or acetic acid mixed with a solution of salts (Bionox) kills microorganisms. It is used only in the STERIS system for heat sensitive and immersible instruments. Processing is 20-30 minutes, temperature is controlled at 131°F; it is cost effective, and environment friendly.

When steam is used to sterilize a rubber tubing or catheter: (A) the lumen must be dried thoroughly before the process begins (B) a rubber band may be placed around it so it does not unwind (C) it should be fanfolded before wrapping(D) a residual of distilled water should be left inside the lumen

(D) Rubber tubing should not be folded or kinked because steam can neither penetrate it nor displace air from folds. A residual of distilled water should be left in the lumen. Rubber bands must not be used around solid items because steam cannot penetrate through or under rubber.

New infectious diseases emerging in the United States include: (A) SARS(B) West Nile virus (C) avian influenza (D) All of the above

(D) SARS, West Nile, and avian flu are all infectious diseases emerging in the United States.

All of the following statements regarding steam sterilization are true EXCEPT: (A) flat packages are placed on the shelf on edge(B) small packages, placed one on top of the other, are crisscrossed(C) basins are placed on their sides(D) solutions may be autoclaved along with other items as long as they are on a shelf alone

(D) Solutions are sterilized alone on a slow exhaust cycle to prevent them from boiling over. The pressure gauge must read 0°F before opening the door. This is so the caps will not pop of.

In a gravity displacement sterilizer, steam enters the chamber through: (A) bottom(B) bottom, back (C) top, back (D) top front

(D) Steam enters the chamber in a gravity displacement sterilizer at the top front of the autoclave.

The only antibiotic that works on MRSA is: (A) gentamycin (B) amoxicillin (C) tobramycin (D) vancomycin

(D) Vancomycin is the antibiotic used to treat MRSA.

Wrapped basin sets may be sterilized by steam under pressure at 250°F for a minimum of: (A) 5 minutes (B) 10 minutes (C) 15 minutes (D) 20 minutes

(D) Wrapped basin sets are sterilized at 250°F for a minimum of 20 minutes. They are placed on their sides to allow air to flow out of them. This also helps water flow out.