Cleaning, Decontamination and Disinfection
Cleaning is the single most important step in instrument reprocessing, and this is one of three HSPA sections that tie for the largest share of the exam at 21 percent each. Blood, tissue, and biofilm form a physical shield that no sterilant can penetrate, so an item that is not clean cannot be reliably sterilized no matter how perfect the cycle. HSPA opens this section not with cleaning technique but with microbiology and worker safety, then moves through point-of-use handling, work-area preparation, manual and mechanical cleaning, water quality and chemistry, disinfection, and the verification testing that proves the process still works.
Microbiology You Actually Need
Microorganisms relevant to reprocessing include bacteria, which exist as vegetative cells or as highly resistant spores; viruses, which may be enveloped or nonenveloped; fungi; and prions, which are misfolded proteins rather than living organisms. Bacterial spores are the reason sterilization exists as a distinct process. Certain bacteria form spores when conditions turn hostile, and those spores survive drying, heat, and many chemicals that easily destroy vegetative cells. That is exactly why spores are the challenge organism in biological indicators: kill a highly resistant spore population and you have killed everything less resistant. The recognized resistance hierarchy, from most to least resistant, runs prions, then bacterial spores, then mycobacteria, then nonenveloped viruses, then fungi, then vegetative bacteria, then enveloped viruses. Memorize the two ends. Prions and spores are hardest to kill; enveloped viruses such as hepatitis B, hepatitis C, and HIV are easiest, because their lipid envelope is fragile — a useful and counterintuitive fact that the exam likes to invert. Bioburden is the number of viable microorganisms present on an item before sterilization, and reducing it through thorough cleaning is what makes the process reliable. Prions get their own line in HSPA's outline under Creutzfeldt-Jakob disease. They are not inactivated by conventional cleaning and sterilization, so instruments used on a patient with known or suspected CJD are handled under a special extended protocol defined by the facility's infection prevention department in line with current CDC and WHO guidance, typically involving keeping instruments moist, avoiding processes that fix protein, and using an enhanced regimen or disposal. The examinable point is not the recipe; it is that CJD is an exception you escalate, not a case you process normally. Biofilm is the other organism-side idea this section tests. When microorganisms are left on a wet surface they attach and secrete a slimy polysaccharide matrix that anchors them and shields them from detergents, disinfectants, and sterilants. Biofilm forms quickly in lumens and on any device left soiled and wet, and once established it requires mechanical action — brushing, flushing, cavitation — because chemistry alone will not reliably penetrate it. That is the microbiological reason behind two rules you already know: clean promptly, and brush lumens rather than merely soaking them. The chain of infection describes the six links an organism must complete to cause disease: an infectious agent, a reservoir, a portal of exit, a mode of transmission, a portal of entry, and a susceptible host. Break any one link and infection is prevented. Hand hygiene and containment of contaminated items break the mode of transmission, protective equipment blocks portals of entry and exit, cleaning and disinfection eliminate reservoirs, and immunization such as the hepatitis B series protects the susceptible host. Cross-contamination is simply the chain running backward through your department: a clean item, surface, or hand touched by something soiled.
Standard Precautions, Bloodborne Pathogens, and Protective Equipment
Standard precautions rest on a simple premise: infectious status is frequently unknown at the moment of contact, so all blood, body fluids, secretions and excretions except sweat, nonintact skin, and mucous membranes are treated as potentially infectious for every patient. In practice, every item arriving in decontamination is handled as if it were infectious, regardless of what is known about the source. The OSHA Bloodborne Pathogens standard makes much of this law rather than recommendation. Employers must maintain a written exposure control plan reviewed at least annually, provide protective equipment at no cost to the employee, provide annual training, use engineering and work-practice controls such as sharps containers and safer devices, label or color-code biohazardous materials, and offer the hepatitis B vaccination series free of charge within 10 working days of initial assignment to a job with occupational exposure. Employees may decline in writing and may later change their minds. After any exposure incident the employee reports immediately and receives a confidential post-exposure medical evaluation and follow-up at no cost. At the decontamination sink the required ensemble is a fluid-resistant or impervious gown or jumpsuit, heavy general-purpose utility gloves rather than thin exam gloves, a face mask combined with eye protection or a full face shield whenever splashing is anticipated, hair covering, and dedicated shoes or shoe covers. Personal eyeglasses do not count as eye protection because they lack side and splash shielding. HSPA calls out donning, doffing, changing frequency, and disposal specifically, so learn the sequence logic rather than just the list. Don clean to dirty, ending with gloves pulled over the gown cuffs. Doff in the order that keeps the most contaminated item away from your skin and face: gloves first, then gown, then eye protection, then mask, with hand hygiene after removing gloves and again after removing everything else. Protective equipment is changed when torn, visibly soiled, or saturated and between tasks that would carry contamination forward, and all protective attire is removed inside the decontamination area before leaving it, because a worn gown is a contaminated item rather than a barrier protecting the clean side. Reusable items are cleaned and disinfected per their manufacturer instructions; disposables go into the appropriate waste stream, with anything saturated or dripping treated as regulated medical waste. Eating, drinking, smoking, applying cosmetics, handling contact lenses, and storing food or drink are prohibited in any area of occupational exposure, including a covered cup on a shelf above the sink, because aerosols settle on the container exterior and a lid provides no protection. Sorting is its own skill in HSPA's outline. Incoming trays are sorted before anything is cleaned, separating reusable instruments from disposables such as single-use laparoscopic tips, blades, trocars, drapes, sponges, and packaging, and separating reusable textiles for the laundry. Getting this wrong costs in both directions: a reusable instrument discarded as trash is an expensive and often unnoticed loss, and a single-use device run through decontamination and returned to a set is a device being reprocessed outside its clearance. Sharps are never handled directly. Any sharp found in a tray is moved with forceps or another mechanical means into a puncture-resistant labeled container, sharps are never recapped or hand-passed, and a loose sharp is reported back to the procedural area as a point-of-use failure rather than silently corrected.
Point of Use and Transport Into Decontamination
Reprocessing begins in the procedural area, not in the decontamination room. Immediately after use, gross soil is removed and the instruments are kept moist so blood and tissue do not dry into serrations, box locks, and lumens. Dried soil is exponentially harder to remove and is the leading cause of instruments arriving with baked-on debris. Moisture is maintained with a damp towel, a pre-treatment foam or spray, or another moisture-retention product used per its manufacturer instructions. Saline must never be used, because chloride ions destroy the passive chromium-oxide layer that protects stainless steel and produce pitting, staining, and eventual instrument failure. Instruments are disassembled to the extent their instructions for use direct, ratchets are left open, heavy items are kept from crushing delicate ones, and the set is transported promptly; when a delay is unavoidable a pre-treatment product buys time. Transport itself is regulated by OSHA. Contaminated items travel in closed or covered, leak-proof containers or carts labeled with a biohazard symbol or color-coded, so anyone who encounters them knows the contents are infectious. A cloth sheet draped over an open cart does not satisfy the requirement. Full cleaning is never performed in the procedural area, because it generates contaminated aerosols in a space meant to be clean. HSPA lists one more duty here that candidates overlook: inspecting for and reporting inadequate point-of-use cleaning. The technician receiving the tray is the person who sees the failure, and the outline treats reporting it as part of the job. Dried blood, loose sharps, uncontained fluid, and missing pre-treatment are documented and fed back to the procedural area, because the department cannot fix a problem it never records.
The Decontamination Area and Equipment Readiness
The decontamination area is a deliberately engineered space, held at negative pressure relative to adjacent areas so that aerosols and chemical vapors generated during cleaning are drawn out and exhausted rather than migrating into the clean workroom or sterile storage. It is kept cool because staff work in full impervious attire and heat stress is real, and its air-change rate, temperature range, and humidity limit come from the edition of ANSI/ASHRAE/ASHE 170 that applied when the system was installed or last upgraded, as covered in Chapter 1. The room is a restricted area, and everyone entering wears full protective attire. Before an item is touched, the workroom itself must be ready. Cleaning tools are selected for the job: brushes sized to the lumen so bristles contact the channel wall along its full length, soft brushes and sponges for delicate surfaces, and lint-free towels. Brushes are inspected, cleaned and disinfected, or discarded on the schedule the manufacturer sets, because a worn brush with splayed bristles no longer reaches the wall of a lumen and a contaminated reusable brush spreads soil from tray to tray. Single-use brushes are discarded after one use, not rinsed and re-hung. Chemicals are identified and prepared per their instructions for use: the correct product for the task, diluted to the labeled concentration with the labeled water, checked against the expiration date, and prepared in the equipment the label specifies. More detergent is not a stronger process; over-concentration wastes money, leaves residue, and can damage instruments, while under-concentration silently fails to clean. Equipment operation is examinable in its own right. Washer-disinfectors, ultrasonic cleaners, cart washers, and leak testers all have operator manuals, and the technician is expected to run them correctly, check and replenish the chemicals they draw from, and read a detergent dosage at the chemical feed line. Daily operator tasks include cleaning strainers and drains, checking that spray arms rotate freely and their jets are not clogged, verifying washer manifolds and basket connections, and knowing which outlets in the room are on emergency power. When equipment alarms or malfunctions, the expectation is to identify the fault, respond per the manual, take the unit out of service if the process is in doubt, and report and document it rather than work around it. Leak testing deserves its own mention because it is the one test that must happen before a flexible endoscope is immersed. A breach in the outer sheath lets fluid into the scope's interior, destroying it and creating a reservoir no cleaning can reach, so the leak test is performed per the instructions for use before immersion and cleaning, and a scope that fails is removed from service without being immersed.
Manual and Mechanical Cleaning
Manual cleaning is done in a three-sink configuration — wash, intermediate rinse, and final rinse — so detergent and loosened soil are not carried forward. The critical technique point is that instruments and brushes stay fully submerged beneath the water surface while brushing, which contains splash and prevents contaminated aerosols. Water temperature must stay below approximately 140 degrees F (60 degrees C), because heat coagulates protein and effectively bakes blood onto the instrument, and because enzymatic detergents lose activity outside their labeled temperature range. Lumens require a brush of the correct diameter and length so bristles contact the channel wall along its full length, followed by thorough flushing; soaking alone or ultrasonic alone will not clear a lumen. High-pressure water guns are useful for flushing channels but must be used below the water line or behind a splash barrier with full facial protection, because they aerosolize whatever they dislodge. Every item is visually inspected at the sink before it moves on, since the sink is where a missed soil problem is cheapest to catch. Ultrasonic cleaners work by cavitation: high-frequency sound waves create microscopic bubbles that implode against instrument surfaces and dislodge fine soil from crevices and box locks. Fresh solution must be degassed before use, because dissolved air absorbs the sound energy and prevents effective cavitation. The lid stays closed during operation to contain aerosols, dissimilar metals are never mixed in the same bath because ion migration causes electrolytic corrosion and plating transfer, items are placed so they are fully immersed and not shielding one another, and the solution is changed at least daily and whenever visibly soiled. An ultrasonic cleaner cleans; it never disinfects or sterilizes. Washer-disinfectors combine spray impingement, detergent, and an elevated-temperature rinse, often 180 degrees F or higher, that provides thermal disinfection and lowers bioburden so items can be safely handled in the clean workroom. Thermal disinfection is not sterilization: critical devices still require terminal sterilization afterward. Load configuration matters as much as it does in a sterilizer, with instruments opened and disassembled, placed in the correct basket or manifold, nothing overlapping or shielding another item, and lumened devices connected to the irrigation manifold rather than laid loose in a rack. Cart washers do the same job for case carts and large equipment. Two special cases round this out. Automated endoscope reprocessors do not replace manual cleaning: a flexible endoscope is leak tested, then manually cleaned and brushed through every channel, and only then placed in the reprocessor with every channel correctly connected. Ophthalmic instruments get their own handling because of Toxic Anterior Segment Syndrome, a severe sterile inflammation of the eye's anterior segment caused not by live organisms but by residues left on the instrument — detergent and enzymatic residue, endotoxin from poor-quality water, viscoelastic left in a cannula, metal ions and deposits. The prevention rules follow from the cause: rinse copiously and completely with the water quality the instructions specify, flush cannulated ophthalmic instruments immediately and thoroughly, never let viscoelastic or detergent dry in a lumen, use single-use cannulas where available, dedicate cleaning supplies to ophthalmic instruments, and follow the manufacturer's instructions on whether a given handpiece may go in an ultrasonic cleaner at all.
Water Quality, Cleaning Chemistry, and Proving the Cleaning Worked
Water is the most heavily used chemical in the department and its quality directly affects outcomes. Utility water is the general-purpose supply used for flushing, washing, and initial rinsing. Critical water has been extensively treated, by reverse osmosis or deionization for example, to remove minerals, ions, and endotoxins, and it is what should be used for the final rinse so residues are not deposited on devices destined for sterile-tissue contact. Hard water leaves a chalky mineral film, and the durable fix is treating the water supply rather than adding more detergent. Detergent selection follows the device instructions for use, but as a general rule neutral-pH products between about 6 and 8 are the safest across the widest range of instrument materials. Strongly alkaline products cut heavy soil but attack aluminum and certain finishes, and acidic products are reserved for mineral scale and rust. Enzymatic cleaners contain protease for protein, lipase for fat, and amylase for starch; they clean but never disinfect or sterilize, and like all enzymes they work only within a labeled temperature and dilution window. Finally, the process must be proven to still work. Cleaning-verification test devices containing a standardized soil are run through mechanical washers at least weekly and preferably each day the washer is used, to confirm that spray arms, pumps, and chemical delivery are still performing. Ultrasonic cleaners get their own efficacy check, either the foil test or a commercial cavitation test device, and automated endoscope reprocessors and cart washers are tested per their manufacturers' instructions. Results are documented and interpreted rather than merely filed, and a failed test means the machine comes out of service and the items it processed since the last passing test are re-evaluated. Waiting for the operating room to complain about visible soil is reactive and allows contaminated devices to reach patients.
Disinfection: Spaulding, Chemistry, and Minimum Effective Concentration
Not everything gets sterilized. The Spaulding classification sorts devices by the risk their use creates and assigns a minimum level of processing to each. Critical devices enter sterile tissue or the vascular system — surgical instruments, implants, needles — and must be sterilized. Semicritical devices contact mucous membranes or nonintact skin, such as flexible endoscopes and respiratory therapy equipment, and require at least high-level disinfection. Noncritical devices touch only intact skin, such as blood pressure cuffs and stethoscopes, and require low-level disinfection. Cleaning is a prerequisite at all three levels, and Spaulding sets a minimum, so a semicritical device may be sterilized if it tolerates the process. The chemical families map onto those levels. Quaternary ammonium compounds are the workhorse low-level disinfectants for noncritical surfaces and patient care equipment. Halogens such as sodium hypochlorite and iodophors are used for surfaces and spills, with hypochlorite at an appropriate concentration being the common choice where sporicidal activity against Clostridioides difficile is needed. Alcohols and phenolics occupy the intermediate and low-level range for surfaces and are not used to high-level disinfect instruments. Aldehydes — glutaraldehyde and ortho-phthalaldehyde — together with certain hydrogen peroxide and peracetic acid formulations are the high-level disinfectants used by immersion for semicritical devices. Three things govern whether a chemical disinfectant actually works. First, concentration: the product must be at or above its minimum effective concentration, the lowest concentration at which the manufacturer's efficacy claims still hold, and reusable solutions are tested with the manufacturer's own chemical test strip on the schedule the label sets, typically before each use or at least each day of use, with the result documented. Second, reuse life: every reusable solution carries a maximum reuse period from the date it was activated or opened, and the solution is discarded at the end of that period or the moment it fails the concentration test, whichever comes first. A failed strip always wins over a remaining reuse date. Third, contact time and temperature: the device must remain fully immersed with all channels filled and no air pockets for the full contact time at the temperature stated on the label, and those values differ between products, so read the label rather than carrying a remembered number from one product to another. On surfaces the equivalent rule is that the surface must stay visibly wet for the entire labeled contact time; one wipe that dries in twenty seconds has not disinfected anything. After high-level disinfection the device is rinsed per its instructions for use, generally with critical or sterile water rather than tap water, then dried, because a wet device stored in a closed container is an ideal environment for waterborne organisms to regrow. Flexible endoscopes are dried with forced filtered air through every channel, often with an alcohol flush per the instructions, and stored hanging or in a validated drying cabinet in a closed, clean, labeled space. The documentation HSPA expects after a high-level disinfection cycle is specific: technician identification, the device and its identifier, the patient if the facility tracks that, the exposure time and solution temperature, the concentration test result, and a lot control number. And there is a corrective-action expectation: a solution that failed its concentration test or ran below its labeled temperature means the devices processed in it were not high-level disinfected, so they are quarantined and reprocessed, the failure is documented and reported, and the cause is investigated, exactly as for a failed sterilization load.
Last updated: September 2026