CRCST Decontamination Study Guide: Cleaning and Spaulding

What this domain covers

An instrument that is not clean cannot be disinfected or sterilized, so the rest of the CRCST builds on this domain. Cleaning, Decontamination and Disinfection is about 21% of the exam, tied for the largest share.

Expect questions on:

• Worker safety: OSHA bloodborne pathogens rules, PPE and basic microbiology
• Setting up the work area
• Manual and mechanical cleaning
• Testing and maintaining cleaning equipment
• Special cases such as TASS, prions and flexible endoscopes
• The levels of disinfection

Safety first: OSHA, microbiology and PPE

The OSHA Bloodborne Pathogens Standard (29 CFR 1910.1030) sets the ground rules for anyone exposed to blood or body fluids. Know these points:

• The employer keeps a written exposure control plan and reviews it at least once a year.
• The hepatitis B vaccine is offered at no cost to at-risk workers. A worker may decline by signing a declination form and can still accept it later.
• The employer provides PPE at no cost.
• Sharps containers are closable, puncture-resistant, leakproof on the sides and bottom, and labeled or red. They are replaced before they overfill.
• Contaminated broken glass is picked up with tongs, forceps, or a brush and dustpan, never by hand.
• No eating, drinking, applying cosmetics or lip balm, or handling contact lenses in the decontamination area.

After a needlestick, wash the site with soap and water and report it right away. Post-exposure care works best when it starts early.

Standard Precautions mean every used item is treated as potentially infectious, whatever the patient's diagnosis.

The chain of infection has six links: infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host. Breaking any link stops the spread. Cleaning removes the agent. PPE blocks the mode of transmission and the portal of entry. Vaccination protects the susceptible host.

Biofilm is a community of microbes inside a slimy, protective layer stuck to a surface. Disinfectants have trouble getting through it, so it must be removed by friction (brushing and flushing). Keep soil from drying and clean soon after use, so biofilm has less chance to form.

Decontamination attire

Wear a fluid-resistant gown with sleeves and heavy-duty gloves whose cuffs go over the gown cuffs. Add a fluid-resistant mask with eye protection (goggles or a full-length face shield). Finish with a hair cover, and shoe covers or dedicated shoes.

Putting PPE on:

1. Gown
2. Mask
3. Eye protection
4. Gloves

Taking PPE off:

1. Gloves (or gloves and gown together)
2. Eye protection
3. Gown
4. Mask
5. Hand hygiene

The room itself is under negative pressure, so air flows in and is exhausted outdoors. The eyewash station must be reachable in about 10 seconds, flushes for at least 15 minutes, and is activated weekly. The departmental considerations guide covers air pressure and eyewash rules for every area.

Point of use and transport

Cleaning starts in the procedure room. The user removes disposable sharps at the point of use. Soil is kept moist with an enzymatic foam, gel or spray, or with a towel moistened with water. Never use saline, because its chlorides pit and corrode stainless steel. Soiled items travel in closed, leakproof, puncture-resistant containers marked as biohazard, kept apart from clean supplies.

Preparing the work area

• Measure both water and detergent to get the dilution on the detergent label. Adding extra detergent does not clean better. It only leaves more residue to rinse off.
• Check the water temperature with a thermometer against the detergent's instructions for use (IFU). Water that is too hot can inactivate enzymes and bake protein onto instruments.
• Change the cleaning solution when it is visibly soiled, and on the schedule in policy and the IFU.
• Enzymes target specific soils: protease breaks down protein (blood), lipase breaks down fats, and amylase breaks down starch. Neutral-pH detergents are the usual choice for instruments.

Manual cleaning

Follow the device IFU above all. If a device's IFU says manual cleaning only, it does not go in the washer. That holds even if the department routinely washes everything.

• Open hinged instruments and take apart multi-part items as the IFU directs.
• Do the first rinse in cool water so protein does not coagulate.
• Brush below the waterline to prevent aerosols.
• Match the brush to the lumen's diameter and length. Throw away single-use brushes after use. Clean and disinfect or sterilize reusable brushes at least daily.
• Never use steel wool or abrasive pads. They strip the passivation layer that protects stainless steel.
• Do not immerse powered equipment unless the IFU allows it. Wipe and brush it as the IFU directs.

Water quality (AAMI ST108): utility (tap) water is used for flushing, washing and intermediate rinses. Critical water, treated by methods such as reverse osmosis or deionization, is used for the final rinse.

Mechanical cleaning and equipment

Ultrasonic cleaners use cavitation to pull fine soil out of hinges and serrations after gross soil has been removed. Degas new solution and keep the lid closed during operation. Do not mix dissimilar metals in one cycle, because ion transfer can etch or pit them. Lensed scopes and powered equipment generally do not go in unless the IFU allows it.

Washer-disinfector cycle: cool pre-rinse, then enzyme or detergent wash, rinse, thermal rinse (disinfection), an optional lubricant phase, and drying. Load the washer with instruments open, concave sides down and heavy items on the bottom. Do not overload it, so the spray reaches every surface.

Testing: cleaning verification tools detect leftover protein, adenosine triphosphate (ATP) or hemoglobin. Soil test devices show whether a cycle removed a standard soil. A high ATP reading means organic residue remains, so the item is recleaned. Ultrasonic cleaners get a cavitation test. Equipment is verified after major repairs before it goes back into service.

Daily checks and troubleshooting:

• Spray arms turn freely and their nozzles are clear.
• Strainers and drain screens are clean (a clogged strainer leaves water standing in the chamber).
• Detergent containers are not empty and dosing lines are primed.
• A load from an aborted cycle is treated as not processed.

Tip from Andrew Hector Smith: When a washer starts leaving soil on instruments, check the simple things first. Look for an empty detergent drum, a strainer full of debris, or an arm blocked by a tall item. Then reprocess everything from the affected loads.

Special cases: TASS, prions and flexible endoscopes

TASS (toxic anterior segment syndrome) is a sterile, non-infectious inflammation of the front of the eye that appears soon after surgery. It is usually caused by residue on intraocular instruments, such as detergent, enzymes, endotoxin or particles. Prevent it by following ophthalmic IFUs exactly, flushing lumens, and rinsing thoroughly with critical water.

Prions, which cause Creutzfeldt-Jakob disease (CJD), are the most resistant agents of all. Brain, spinal cord and eye tissue are high risk. Follow the facility's written prion policy, and keep instruments moist so the soil never dries.

Flexible endoscopes follow this sequence:

1. Pre-clean at the point of use: wipe the insertion tube and suction detergent through the channels.
2. Leak test before the scope is immersed. A scope that fails comes out of service.
3. Clean manually.
4. Do high-level disinfection (or sterilization) in an automated endoscope reprocessor (AER) or by hand, then rinse.
5. Flush with alcohol and dry with forced air.
6. Store hanging vertically in a ventilated or drying cabinet with valves removed.

If the AER shows a flow alarm, the scope has not been disinfected and must be reprocessed.

Disinfection and the Spaulding classification

Microorganisms from least to most resistant:

1. Enveloped viruses and vegetative bacteria
2. Fungi
3. Non-enveloped viruses
4. Mycobacteria
5. Bacterial spores
6. Prions

A product that kills tuberculosis is rated intermediate-level. Disinfectant levels to know:

The FDA clears disinfectants for devices, and the EPA registers surface disinfectants. Non-critical patient care equipment is covered in the patient care equipment guide, and sterilization methods in the sterilization process guide.

For high-level disinfection to work:

• Test the solution with minimum effective concentration (MEC) test strips before each use, as the IFU directs, and document the result.
• If the solution fails, discard it and replace it. Never top it off.
• Run a quality-control check on each new bottle of strips, as the strip IFU directs.
• Meet the labeled temperature and contact time, rinse thoroughly, and transport the device in a clean, covered container.
• Keep containers covered and the room well ventilated to limit vapor exposure.

Test yourself with the free cleaning and decontamination practice questions, each with the answer explained. To see which domain to study first, take the free CRCST diagnostic test.

Sources

The Cleaning, Decontamination and Disinfection questions cite these documents, by document and, where we can confirm it, chapter or section. We never reproduce them.

1. HSPA Sterile Processing Technical Manual (57 questions)
2. ANSI/AAMI ST79 (25 questions)
3. CDC Guideline for Disinfection and Sterilization (15 questions)
4. OSHA 29 CFR 1910.1030 (7 questions)
5. ANSI/AAMI ST58 (6 questions)
6. ANSI/AAMI ST108 (5 questions)
7. ANSI/AAMI ST91 (5 questions)
8. OSHA 29 CFR 1910.1200 (1 question)
9. OSHA 29 CFR 1910.151 (1 question)

Found a mistake? Use "Report a problem" under any question, and Andrew Hector Smith checks it.

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