Objectives of cleaning and disinfection

Cleaning is intended to remove matters (e.g., patient secretion and inorganic material (e.g., salts) from surfaces of reusable medical devices (RMD)
Disinfection, is intended to reduce the microbial load

Cleaning and/or disinfection takes place in preparation for sterilization or with disinfection as a final step before use of the RMD.

  • Before sterilization, the primary objective is cleaning i.e. the withdrawal of matter which would interfere with the sterilizing agent  and generate endotoxin or pyrogen risks. Disinfection improves the preparation of RMD for sterilization and is required or recommended in some countries as an occupational health and safety measure for operators in charge of packaging .
  • As the last step before use of the RMD, the objective of cleaning & disinfection is to render the RMD safe for the patient according to Spaulding classification principles.

      In the present guide cleaning&disinfection is preferred to decontaminationPrinciples of cleaning

Cleaning consists  of washing followed by rinsing

  • Washing is the removal of soils from surfaces of the RMD by water containing a cleaning agent.
  • Rinsing evacuates the soils detached by washing as well as detergent residues which would chemically interact with disinfection or sterilization agents.

Main categories or detergent are : neutral, with or without enzymes, mild alkaline with or without enzymes, alkaline

Most detergent formulations include a surfactant (to reduce the surface tension of water thus easing the wetting of surface and breaking up of soils).
Other components of detergents are buffers to improve the compatibility with RMD material and Softeners to reduce the potential negative effect of hard water (spotting and deposit on surface).
Neutralizers may be applied after some alkaline cleaners.
Cleaning agent comply to applicable local detergent regulation      See disinfection paragraph for formulation used for combined cleaning and disinfection     They is no international standard  for detergent but methods and thresholds are becoming available to evaluate cleaning efficacy.

Cleaning is performed according to instructions for use of RMD manufacturer and  cleaning agent manufacturer

The conditions for efficient washing are illustrated by the Sinner circle1. Mechanical action by manual brushing, flushing, swabbing or wiping, automated spraying or flushing, cavitation (in ultrasonic cleaner).2. Chemical action of cleaning agents which decompose protein, fats, ease the removal or soil from surfaces3. Contact time of all RMD surfaces with the cleaning/water solution4. Temperature of the cleaning solution.Concentration, exposure time or temperature above those specified by IFU may present risk for operators and damage on RMD and do not mean higher cleaning efficacy. Progress of minimally invasive surgery often means complex, narrow geometries (lumen, cavities, hinges) more susceptlble to retain soil, delicate and hidden to visual control. If specified by RMD manufacturer instruction for use (IFU), multicomponent RMD are disassembled prior to cleaning. 

Consistency of cleaning (i.e. rigourous application of cleaning procedure after each use of the RMD) is key to avoid the progressive formation of biofilm or build-up of mineral deposit in narrow spaces or cavities

Once installed, biofilms (for instance biofilms of Pseudomonas aeruginosa) protect the germs from disinfection agent. Biofilms are likely to grow and become more difficult to withdraw even if next cleaning is well performed.Build-up of mineral deposit (for instance scale) ease the anchorage of germs and biofilms, damage instruments and impair their functionalityScratches or rust facilitate the anchorage of soils and biofilms. Damaged or rusted RMD are sent for maintenance or discarded.

Principles of disinfection Disinfection is chemical or thermal

  1. Chemical disinfection with a disinfection or cleaning & disinfectant formulation is followed by rinsingdrying and when recommanded by RMD IFU, by lubrication Chemical disinfection is mainly used for thermosensitive RMD.

Rinsing with adequate water quality removes chemical agent residues. Rinsing after disinfection is called final rinsing to differentiate it from intermediary rinsing which takes place after cleaning.Drying with adequate air quality removes residual humidity which favors recontamination and impairs sterilization. In some countries, alcohol rinsing is used to accelerate drying (in particular for GI endoscope reprocessing). This practice is not allowed in other countries (for instance Europe) due to fixative properties of alcohol.

RMD is immersed in a bath (manual process), exposed to spray (automated process) or wiped (only when immersion or spray are not allowed by RMD manufacturer IFU).
Chemical disinfection is achieved when all RMD surfaces have been exposed to the disinfecting formulation at concentration, temperature and for the contact time specified by the disinfectant manufacturer instructions for use (IFU).
Disinfection is characterized by the achievement of a specified log10  reduction on of representative test microorganisms (Unlike sterilization which targets eradication of all microorganisms) 

Categories of microorganisms are listed below in order of usual growing order of resistance to disinfectant (examples of microorganisms frequently used for tests appear in brackets)Vegetative bacteria – gram negative and gram positive (for examples, Staphylococcus aureus, Pseudomonas aeruginosa)Fungi/yeast (Aspergillus niger, Candida albicans)Virus : enveloped (lipid or medium size) viruses such as HIV, herpes, hepatitis are less resistant than bacteria while non-enveloped (nonlipid or small viruses such as polio).Mycobacteria (M. tuberculosis, M. terrae, M. avium)Spores (Bacillus. atropheus, B. subtilis, B. cereus, Clostridium sporogenes)

Prions are more resistant than all the above.Each claim (bactericidal, fungicidal, virucidal, mycobactericidal, sporicidal) is validated separately. For instance, a successful sprocidal test, does not yield a claim with germs of lower resistance.Tests microrganisms are protected by artificial soil simulating the level of organic matter which may be found on RMD. Disinfectant used after cleaning are tested in clean conditions. Disinfectant used for combined cleaning and disinfection are tested in dirty conditions.There are no unique ISO international standards for evaluation of disinfecting activities. Tests protocols are hence subject to regional variances. For instance, it is generally agreed that carrier tests are the more representative for RMD but despite harmonization effort under the Organisation for Economic Co-operation and Development (OECD) test protocols (methods and log reduction objectives) differ (AOAC or ASTM in USA, phase 2.2 EN test in Europe).       Carrier test are methods in which microorganisms are inoculated and dried on an inanimate surface before being immersed in the disinfection solution.

Chemical disinfectants formulations are aldehydes (Glutaraldehyde, Ortho-phthalaldehyde-OPA) and peracetic acid. Detergent-disinfectants use chemical with dual properties or mixtures of detergent and disinfectant

Aldehydes have good compability with RMD. Room ventilation is required for glutaraldehyde due to irritancy and potential toxicity.OPA is better tolerated. Aldehyde are fixative of protein and must be only be used after thorough cleaning. Formaldehyde which also belongs to the aldehyde disinfection family is a carcinogen and not anymore used.Peracetic acid has a broad spectrum of activity and good efficacy on spores but is less stable and more corrosive than aldehydes. Unlike aldehydes it produces no toxic waste.Other formulations based on hydrogen peroxide, chlorine based, chlorine dioxide (ClO2) may be found. Compatibility with materials of RMD must be checked.  Alcohol is not an effective disinfectant for RMD (it does not penetrate well into organic material and is not sporicidal) .Combined cleaning and disinfecting chemical formulations are mixtures of quarternary ammonium, biguanide, guanidine, alkylamine, enzymatique, alkaline. Aldehyde based cleaner-disinfectant are avoided due to their fixative properties.

Choice of disinfectant is made in partnership with infection control. Disinfectant must be effective on the type and quantity of mircroorganisms which may be present on the RMD.

For instance, nature as well as amount of microorganisms present on RMD are not be the same for gastroscopes and bronchoscopes.Additional precautions may be required in special circumstances (for instance a C. Difficile breakout).Fragile or immunodeficient patients may require additional precautions.Choice of formulation might be influenced by local habits, recommendations or regulations, for instance in regards to fixative properties or for waste management considerations.
  1. Thermal disinfection is performed in automated washer-disinfectors (WD) with hot water at specified temperature Thermal disinfection is commonly used for surgical instruments intended for steam sterilizationLubrication is applied as recommended by RMD manufacturer IFU.
    Reusable containers and other heat and moisture compatible items are also thermally disinfected.In thermal WD Disinfection and rinsing are combined. Thermal disinfection provides good drying. Thermal disinfection is also efficient for self-disinfection the washer-disinfector.

          Some manufacturers may however offer or recommend periodic self-disinfection cycles

Thermal disinfection, is achieved when all RMD surfaces have been exposed to hot water at a defined temperature for a minimum contact time.
Thermal disinfection is efficient to eliminate most microorganisms. Spores show higher resistance. Thermal disinfection can be characterized by the Aconcept

The improvement of lethality with hot water temperature can be predicted. For instance, for heat resistant microorganisms, 10 minutes at 80°C has the same lethality effect as 1 minute at 90°C or 100 minutes at 70°C.  By convention the time (expressed in second) to obtain a given log reduction at 80°C serves as a reference and called Afor heat resistance microorganism. In the above example A0 equals 600 s (10 minutes at 80°C). Higher A0 means longer exposure time at 80°C or shorter times at higher temperature according to A0 equation.      A0 = Σ10[(T-80)/z] x êtSee annex B of international standard ISO 15883-1 for more explanation. Local regulation, recommendation or habits define the A0 thresholds according to the level of contamination of the RMD and intended use.A0 of 60 s is commonly recognized as the minimum to be targeted for low risk items according to Spaulding classification principles. 600 s is the minimum for other items. Automated WD for surgical instrument complying to ISO 15883-2 must have one cycle with an A0 value above 3000 (e.g. a theoritical value of 50 minutes at 80°C  or practically  5 minutes at 90 °C or 2 min and  30 s at 93 °C).A0 values of 3000 or above are recommended in some countries. Others consider 600 s as sufficient for most items (considering that thermal disinfection always takes place after cleaning and that residual spores (if any) will be eradicated by sterilization     Some national regulation (for instance FDA in USA) may not recognize the Aconcept and have other ways to specify the minimum level of disinfecting efficacy to be achieved by thermal washer for RMD on a defined thermophilic mycobacterium species.

After disinfection, RMD may still carry some microorganisms, residual humidity and are not protected by packaging. Precaution must be taken to limit environmental and handling contamination.
Maximum storage time after disinfection are usually defined by local recommandation or regulation.Choice of cleaning & disinfection process

The 4 main categories of cleaning and/or disinfection processes are

  1. Manual cleaning & Disinfection. RMD are immersed and manually processed in cleaning and then disinfection baths or in combined cleaning&disinfection solutions. When immersion is not allowed by RMD manufacturer IFU, RMD is wiped.
  2. Automated washer disinfectorDisinfection if thermal or chemical
  3. Ultrasonic cleaning, when approved by RMD manufacturer IFU
  4. Automated Endoscope Reprocessors (AER) for thermosensitive flexible endoscopes

Choice  of cleaning & disinfection process, cleaning, disinfection and lubrication agents take into account  instruction for use (IFU) of RDM, detergent and cleaning equipment manufacturers

RMD manufacturer IFU specify the compatible cleaning and disinfection methods. Compatibility means that evidence are available that the RMD can be efficicently cleaned and disinfected and remains functional and safe for use. If appropriate, the manufacturer of the reusable medical device (RMD) indicates a maximum number of reprocessings allowed.WD and ultrasonic cleaners manufacturersrecommend the type of detergent and disinfectant approved and tested for use with their technology as well as dosage. Manufacturer of the equipment checks efficacy of cleaning and disinfection agent approved for use in the more unfavorable conditions (for instance lowest value of the temperature range)IFU of cleaning and disinfecting agent Manufacturers – indicates if the chemistry is intended for manual, automated or ultrasonic cleaning – gives dosage, contact time, T°C, water quality  for each usage – specifies precaution for use, waste management, time during which an open detergent or disinfectant  bottle can be used. Labeling carries the expiry date.

When allowed by RMD manufacturer IFU,automated cleaning and disinfection processes (WD and AER) are preferred to manual.

Washer-disinfector (WD) and automated endoscope reprocessors(AER) are more reproducible (less human dependant) and safer for operators (reduction of exposure to chemicals, aerosols, handling risk).

Automatic recording allows reliable documentation.

For cleaning and disinfection of RMD in preparation for steam sterilization International standards express a preference for thermal disinfection

   ISO 15883-1says: Thermal disinfection processes are more easily controlled and avoid the hazards to staff, patients and the environment that can occur through the use of chemical disinfectants. “Thermal disinfection is efficient to eliminate most microorganisms (except spores) and provide good rinsing and drying”.

Manual or ultrasonic pre-cleaning may be required before automated cleaning and disinfection of complex and/or heavily soiled RMD

Place of ultrasonic cleaning in national or regional guidelines depends on regional habits, guidelines or regulations. In some countries ultrasonic cleaning is only used for pre-cleaning of heavily soiled or complex RMD before automatic cleaning. In other countries, ultrasonic cleaning may plays a larger role.

Manual wiping is used when immersion in bath is not allowed by RMD manufacturer IFU

      International standard ISO 176648says :

At least one validated automated cleaning method (which may include a validated manual pre-cleaning method) shall be specified unless the medical device cannot withstand any such process, in which case a statement shall be provided which alerts the user to this issue……. A validated method of manual cleaning shall be specified if automated cleaning is not possible.

if the medical device is intended to be disinfected, at least one validated automated disinfection method shall be specified unless the medical device cannot withstand any such process, in which case a statement shall be provided which alerts the user to this issue…… If the medical device is intended to be disinfected a validated method of manual disinfection shall be specified if automated disinfection is not possibleImplementation of manual cleaning & disinfection process

Manual Cleaning & disinfection processes are prepared and implemented according to written standard operating procedure (SOP).

Preparation of Cleaning and disinfection baths is according to the IFU of the cleaning agent manufacturer. Water quality used for each step is as recommended per IFU (water hardness, pH, temperature).

Brushes, single-use cloth and other cleaning accessories are as recommended by RMD Manufacturers instruction for use (IFU) or equivalent to them (usually soft nylon bristle brushes). Unless clearly specified in the RMD metallic brushes are not used. Type, size (diameter and length), bristle type and material of brushes used to clean lumen are those indicated in RMD manufacturer IFU. They should be the same diameter as the lumen to ensure all internal surfaces can be reached and long enough to exit the distal end of the instrument. RMD manufacturers may have special recommendation for optics surfaces.
If not single use, brushes are daily cleaned, disinfected (preferably thermal) and dried. Brushes are checked after each use and replaced when damaged.

Steps are as follows:

  1. The RMD is completely immersed in the cleaning bath. Articulated RMD are open to minimize obscured surface area. Bubbles trapped in cavities and channels are eliminated. Some manufacturers may recommend flushing through at a specified pressure for a defined time. RMD remains immersed during cleaning. Cleaning operations are performed in a manner that limits production of aerosols or dispersion of potential contaminated chemicals or water.
  2. Gross soil is removed. Accessible surfaces are cleaned with appropriate tools until visibly cleaned. RMD with articulations are moved (open and close at least 5 times). Channels are swabbed. Swabbing is always performed in the same direction from the less soiled to the most soiled end (at least 5 times). Other hard to access area are flushed with syringe, water gun or hand pump
  3. RMD is rinsed under running water (at least for 10 s for all external surfaces). Articulations are moved. Channels are flushed for at least 10 s. RMD is allowed to drain to avoid dilution of disinfection solution. Rinsing removes visible or non visible soil as well as residual detergent which might react with disinfectant.
  4. Absence of soil is visually checked. RMD and canulated device are placed on a white clean surface (for instance white crepe papier) and observed under illuminated magnifier
  5. RMD is immersed in disinfection bathArticulations are moved at least 5 times. It must be checked that internal lumen and cavities and completely immersed and in contact with solution.
  6. RMD is rinsed with appropriate water quality: 10 s at least for all external surface and 10 s flush for each channel.
  7. RMD is dried with adequate compressed air quality. If compressed air is not available or not recommended by the manufacturer RMD is air or hand dried with a disposable clean, non-linting cloth.

If manual cleaning and disinfection is performed with a cleaning-disinfecting agent steps 2 and 3 are skipped and visual control is performed after 6.

The disinfection bath is preferably single use. If not, the disinfectant manufacturer specify the maximum number of reuse and provide recommandations and means to control that the concentration of disinfection agent is above minimum levels required for efficacy.

SOP details the steps and, for instance, provide quantitative and qualitative indication for manual operation, number of time a channel should be brushed or flushed and criteria, accessories to be used

It might be convenient to organize Manual cleaning and disinfection SOP  according to RMD configuration. 

For RMD or parts of RMD which cannot be immersed (for instance some motors, batteries) are wiped and rinsed with disposable cloth soaked with detergent and/or disinfectant agents. Consistency of manual wiping is difficult to obtain. Manual wiping is used when non other cleaning and disinfection methods are applicable. Manual wiping is carried according to RMD manufacturer IFU.

Manual wiping steps are as follows:

  1. Wipe with a disposable, clean, non-linting cloth and detergent until all cleaning agent residue is visually removed. Check that moisture does not penetrate into critical parts of the device (for instance power or electronic connections)
  2. Rinse the RMD by wiping surface thoroughly with a damp, disposable, clean, non-linting cloth with objective to withdraw disinfection residues.
  3. RMD is visually controlled if needed with an illuminated magnifier
  4. Dry with medical-grade compressed air. If compressed air is not available or not recommended by the manufacturer of the RMD, air dry or hand-dry using a disposable clean, non-linting cloth. Disposable cloth are discarded

If wiping is performed with a cleaning.disinfecting agent (non-critcial RMD only) steps 2 and 3 are eluded.Implementation of ultrasonic cleaning process

Ultrasonic cleaners use cavitation to detach soils from RMD. 

Ultrasound generators produce acoustic waves (waves frequency generally ranges between 35 and 45 kHz). Acoustic waves create bubbles which implode as they become larger and unstable. Implosion creates a vacuum in the solution (cavitation) that mechanically draws debris from the surface of the RMD.Ultrasonic cleaners encompass a wide range of technologies from the basic ultrasonic cleaning equipment with the user performing all the function of filling, rinsing, draining to automated equipment. Ultrasonic cleaners could be categorized as follows : (basic) ultrasonic cleaners, ultrasonic irrigators or irrigator-washer or irrigator washer-disinfector.

Efficacy of cavitation is improved by adapted cleaning agent.

Ultrasonic cleaner are often used for pre-cleaning (prior to Washer-disinfector) of complex RMD.

Ultrasonic cleaners are well adapted for stainless steel devices with reamers (rasps) , lumen, sleeves or complex shapes difficult to access.

Ultrasonic cleaning is used only if not contraindicated by RMD IFU

Ultrasonic cleaning is not recommended for RMD with :Some types of adhesivesMixing different metals (for instance scissors with screw, needle holder, clamps with jaws in tungsten carbide, chrome or nickel steel)Optics (because of the risk for adhesives and seals)Power toolsOther active items such as phacoemulsification or dental handpieces

Ultrasonic cleaning processes are prepared and implemented according to written standard operating procedure (SOP).adapted to ultrasonic cleaner features.
Detergent must be suitable for ultrasonic cleaner.
Before immersion in ultrasonic bath RMD gross soil is removed.

Principles for bath preparation, loading and unloading are as follows

  1. Follow instructions of ultrasonic cleaner and detergent manufacturers for dosing and temperature of bath. Water temperature is between 27 °C (80 F) and 43 °C (109 F) and never above 60 °C (140 F) because most proteins denaturate above that temperature. For ultrasonic systems without thermoregulation room temperature might be preferable as energy delivered by ultrasonics wave will increase the temperature of the bath.
  2. The bath is degassed at each filling. This is done by filling the unit, closing the lid and running a cycle for 5 to 10 minutes
  3. RDM are placed in a tray (never directly on tank end) widely openednot superposed to avoid shadow. When applicable, connect lumen devices to flushing ports. If other specific positioning accessories and features are used, refer to manufacturer IFU.
  4. The cavitation process may create aerosols, the ultrasonic bath should hence have a lid that must remain closed during the cleaning process.
  5. Process timeis as recommended per manufacturer (usually between 5 and 10 minutes)
  6. If rinsing is not performed by the ultrasonic cleaner, the RMD is rinsed and dried manually

The bath is preferably changed after each use (i.e. after reprocessing cycle). Ultrasonic cleaning equipment is cleaned every day that it is used and according to manufacturer IFU. Local recommendations specify  that it has to be refilled after each use or daily and each time the bath is visibly soiled.

     National regulation or recommandation may forbid the use of ultrasonic cleaners if a prion riskhas been identifiedImplementation of washer-disinfector processes

Washer-Disinfectors spray or flush pressurized water mixed with a detergent on surfaces of RMD and lumen. The cleaning stage is followed by a thermal or chemical disinfection.
Various types of WD and applicable international standards are as follows :

  1. Washer-disinfectors with thermal or chemical disinfection stage for surgical instruments. There are available in different construction, e.g. single chamber (load-through or single door) or multichamber version.
  2. Thermolabile endoscope washer-disinfector
  3. Cart-washer for the cleaning of carts, reusable containers, surgical basins and other non-invasive , non-critical medical devices.
  4. Multichamber WD
  5. Washer-disinfector for dental handpieces and turbines

     International Standard ISO 15883 family includes general requirements ISO 15883-1 and specific parts dedicated to each type of WD

  • WD for instruments comply with ISO 15883-1 and -22,3
  • WD for thermolabile flexible endoscope comply with ISO 15883-1 and -41,5
  • Cart washer comply with ISO 15883-1 and -6 (thermal disinfection) or -7 (chemical disinfection)1,6,7

There is currently no ISO standard for dental handpieces and turbines

     Compliance to ISO 15883-1and subsequent parties2,3,4,5,6,7 may be required (for instance in Western Europe)

WD processes are prepared and imlplemented according to written standard operating procedure (SOP).

Heavily soiled and/or complex RMD may require manual or ultrasonic precleaning

As per RMD manufacturer IFU, RMD is disassembled, cap, gaskets, all disposable items are removed. Hinged surgical instrument with handles (scissors, clamp, and forceps) are opened (generally at 90°) according to manufacturer IFU

The SOP describes the load configuration(i.e. the type of RMD which can be reprocessed together in a given cycle).
RMD are placed in a tray or positioned on suitable modules and/or connected to irrigation ports (for lumen devices).

If needed hold-down screens or retaining systems prevent dislodging of RMD during the cycle.Fragile or small devices are protected (installed in trays with lid and/or blocking accessories).Heavy or large items are preferably placed on lower-levelsHollow items are turned downwards for water evacuationRacks should never be overloaded. All RMD surfaces must be exposed to water spray (no shadowed surface).Specialized racks and loading equipment are required for RMD with complex geometries and lumen. Racks are for instance available for laparoscopic surgery, dentistry, robotic surgery.Minimally Invasive Surgery (MIS) instruments with lumen are  connected to adaptors. Adaptors are carefully chosen for proper flushing pressure and flow. Clear procedures are key to optimize the layout, avoid connection mistakes or accidental disconnection during cycles.  In case of especially narrow lumina a filter  is required to prevent particles from entering the lumen.

Before cycle launch it is checked that spraying arms are unobstructed.

All phases of WD cycles are automatically run, controlled and recorded. WD cycles usually start with a pre-washing phase (included in the automated cycle) to wet the RDM but does not replace ultrasonic or manual pre-washing.

  • Pre-washing wets the RMD (without detergent) to ease soil removal.
  • Washing is at temperature is at temperature specified by detergent manufacturer (usually around between 45 °C. Mechanical action is by spray, circulation or irrigation). cleaning solution is single use
  • Intermediary rinsing may include a neutralization stage (for some cleaning agent formulations)
  • Thermal (preferred if applicable) or chemical disinfection is adapted to contaminants and log reduction targets. In chemical WD, if the disinfection is not single use, the maximum number of reuse specified by the disinfectant manufacture is respected. Recommendations and means are provided by the manufacturer to control that the concentration of disinfection agent is above minimum levels required for efficacy.
  • Final Rinsing. In thermal WD thermal disinfection also serves as a rinsing phase.
  • Drying is obtained by circulation of hot air (of appropriate air quality)

Implementation of automated endoscope reprocessor (AER) processes

AER are used for gastro-intestinal (GI) scopes (GI) and some other semi-critical single lumen flexible endoscopes. AERspray or flush pressurized water mixed with a detergent and then a disinfectant on surfaces and lumens of the endoscopes. All phases are automatically run, controlled and recorded.

AER processes are prepared and imlplemented according to written standard operating procedure (SOP).

In chemical WDincluding AER – cleaning solution is single use, disinfection solution is preferably single use. If the disinfection solution is reusable, the user respect the maximum number of reuse specified by the disinfectant manufacturer. Recommendations and means are provided by the manufacturer to control that the concentration of disinfection agent is above minimum levels required for efficacy.Cleaning & disinfection and quality management

Written cleaning & disinfection standard operating procedures (SOP) are prepared in accordance with quality management principles. Each step of the cleaning& disinfection process is an improvement to the former steps and does not impair the  efficacy of the following stages

For instance, final rinsing and drying are performed with adapted Water quality and Air quality to avoid recontamination of the disinfected RMD. Lubricant must be compatible with the RMD and with the sterilization process. Incompatible lubricants can inhibit sterilization, create harmful by-products, and damage the device.

User supervises or perform process validation and in particular controls that

  • Installation of cleaning and disinfection workstation or equipment is conform to manufacturer recommendations
  • Documentation (for instance, IFU, test and calibration certificates) are available
  • Standard Operating Procedures (SOP) are up to date 
Written standard operating procedures (SOP) are available for each RMD or group of RMD requiring similar cleaning and disinfection process. For newly purchased RMD, a new SOP is defined if an existing one cannot be used.When possible SOP provide quantitative and qualitative criteria for manual operations (for instance brush until no soil is visible, number of time a lumen should be swabbed etc..)
  • Systematic and periodic routine controls are in place (see below)
For all cleaning & disinfection process, RMD are visually controlled for cleanliness. If soils are visible RMD are cleaned again.
For washer disinfector (WD) and automatic endoscope reprocessors (AER) processes aiming compliance to international standard  ISO 15883-1, cleaning efficacy is controlled at periodicities and according to methods described in ISO 15883-1 and 15883-55. For WD and AER not aiming compliance to ISO 15883 validation framework proposed by ISO 15883 and 15883-5 methods may be used
Microbiological and chemical quality of incoming and final rinsing water quality are controlled according to local regulation and meet specifications of equipment, detergent and disinfectant manufacturer IFU.
Periodical Microbiological controls of RMD may  be required by local regulations (for instance annual control of flexible endoscopes in some countries).
  • Occupational health & safety considerations (in particular exposure to liquid and vaporized chemicals, aerosols and injuries by potentially contaminated RMD)
  • Reprocessing fluids are discarded according to local waste management rules.
  • Training (including training on occupational health & safetymeasures) are up to date, executed and training certificates are available.
  • Maintenance plans are in place for washer-disinfector, ultrasonic cleaners and dosing pumps.
  • Traceability is operational

WFHSS key recommendations for cleaning & disinfection

  1. Cleaning & disinfection process complies to instructions for reprocessing of RMD manufacturer. It is implemented according to IFU of RMD, detergent, disinfectant and reprocessing equipements manufacturers
  2. Thorough and consistent Cleaning  is essential for efficient disinfection and sterilization. Progress of minimally invasive surgery often means complex, narrow geometries, difficult to access and hidden to visual control. Inconsistent cleaning allows the progressive development of biofilms or mineral deposits.
  3. Objective of disinfection depends on intended use of RMD
  • When done in preparation for sterilization, disinfection improves the preparation of RMD for sterilization. It may be required or recommended in some countries as an occupational health and safety measure.
  • When disinfection is the last step before use of the RMD on patient targeted efficacy is defined, with infection control, according to Spaulding classification principles .
  1. Automated cleaning and disinfection in WD or AER is preferred to manual
  • Ultrasonic or manual precleaning may be needed for complex or heavily soiled RMD. Ultrasonic reprocessing must be allowed by RMD manufacturer IFU.
  • Thermal WD are preferred for heat and moisture resistant RMD.
  • WD and AER are preferably compliant to international standardsprocesses complying to international standards1,2,3,4,5,6,7
  1. Non automated cleaning & disinfection is performed with care and consistency. When allowed by RMD manufacturer IFU, ultrasonic cleaning is efficient for devices with complex geometries. Wiping is used only when RMD manufacturer IFU do not allow immersion. Combined manual  cleaning and disinfection with a cleaning&disinfecting formulation may be used on low risk items according to Spaulding classification principles or, if permitted by local regulation, in preparation for sterilization.
  2. Manual and automated cleaning and disinfection processes are implemented according to quality management principles. Standard operating procedures (SOP) are up to date and describe systematic or periodic (visual controls of cleanliness and dryness are systematic). Process validation concerns both automated and manual processes.   International standards1,5 Operators training is regularly updated and controlled. Appropriate occupational health and safety measures and traceability are in place.
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Combination of all technical and associated administrative actions intended to keep equipment at a state in which it can perform its required function, or restore it to such a state (ISO 11139 : 2018)


Packaging is intended to preserve the sterility of teh reusable medical device (RMD) until its use.

Reusable containers

Rigid sterile barrier system designed to be repeatedly used (ISO 11607-1 2018)

International standards

For the puropose of these guidelines, International Standard means standardsor guidance published by international standardization organizations such as ISO or CEN.
Go to the international standards paragraph or Regulation and standards chapter 


Prion is a small proteinaceous infectious unit that appear in a variety of neurodegenerative diseases, including bovine spongiform encephalopathy, Creutzfeldt-Jakob disease, and scrapie. They derive from a normal body protein that becomes irreversibly misfolded and proliferates primarily in the central nervous system.
Prions are highly resistant to disinfection and sterilization

Fixative properties

Some sterilizing, cleaning and disinfecting formulations are known to favor the adherence and resistance of proteins, including prion on RMD surfaces.

Air quality

Levels of purity of ambient air and compressed air used for drying.

Water quality

Chemical, physical, biological, and radiological characteristics of water used for cleaning, disinfection, rinsing and steam sterilization of RMD.

Point of use reprocessing

Processing operation performed at point of use of the Reusable Medical Device (i.e. operating theatre or care unit)

Quality management 

Quality management includes all the activities that organizations use to direct, control, and coordinate quality. These activities include formulating a quality policy and setting quality objectives. They also include quality planning, quality control, quality assurance, and quality improvement.
In the present guide the quality management chapter includes a description of the processus approach, performance evaluation, risk and non-conformity management, documentation management and traceability

Go to quality management chapter →

Spaulding classification

The Spaulding classification qualify the RMD as non critical when they touch intact skin, semi-critical when they are brought in contact with mucous membranes and critical when they enter sterile body cavities. Processing requirements increase with level of risk involved in their use.

Occupational health and safety (OHS)

OHS deals with all aspects of health and safety in the workplace and has a strong focus on primary prevention of hazards (WHO : 2016)

Reusable medical device (RMD)

For the present guidlelines reusable medical device (RMD) means:

  • an item that is not intended by its manufacturer for single use.
  • A medical device designated or inrtended by the manufacturer as suitable for reprocessing.

The reprocessing of single use medical device is outside the scope of theses guidelines.
Medical device regulations vary between regions. Some items may not be registered as medical devices in some regions.


Sterilization is intended to renders the reusable medical device free from viable microorganisms. Sterilization is implemented on a clean RMD. Most common Sterilization process is steam. Low temperature sterilization processes are available for heat sensitive RMD

Disinfection :

Process to reduce the number of viable microorganisms to a level previously specified as being appropriate for a defined purpose (ISO 11139 : 2018) 

Cleaning :

Removal of contaminants to the extent necessary for its further processing or for intended use (ISO 11139 : 2018)  

Other definition: The first step required to physically remove contamination by foreign material, e.g. dust soil. It will also remove organic material such as blood, secretion, excretion and microorganisms, to prepare a medical device for sterilization or disinfection (WHO : 2016) 

Cleaning may be combined to disinfection in cleaning & disinfections processes (for instance in automated washer-disinfectors)

Tooltip Content

Sterilization :

Process used to render product free from viable microorganisms (ISO 11139 : 2018)

  • courthouse-3-1 Sterilization is intended to renders the reusable medical device (RMD) free from viable microorganisms.

Standard operating procedures

SOP’s are written, step-by-step instructions that describe how to perform a routine activity. SOP’s aim to achieve efficiency, quality output and uniformity of performance, while reducing miscommunication and failure to comply with industry regulations.

Routine control (or routine test)

technical operation conducted periodically to establish that the operational performance of the equipment or process remains within the limits established during validation (ISO 11139 : 2018) 

“The WFHSS executive committee is pleased to put the WFHSS Guidelines at your disposal.
They have been written for all the professionals working directly or indirectly in the field of the reprocessing of Reusable Medical Devices (RMD) used in Health Care facilities.

They are the result of a consensus from a review of national practices, standards, regulations.
They are intended to provide guidance and the state of the art recommendations from an academic world society focused on science but their purpose is not to supersede local regulation, standards or guidelines.
They will be updated regularly to follow the evolution of the science and the evolution of the RMD and the technologies.

Your feedback is essential to contribute to the improvement of the Guidelines , feel free to use the form to send your comments or suggestions.

We wish you interesting reading!

On behalf of the Executive Committee

Dr Christine DENIS, President”  

Fixative properties

Some sterilizing, cleaning and disinfecting formulations are known to favor the anchorage of proteins, including prion on RMD surfaces. For instance, dry heat, ethylene oxide, aldehyde based sterilizing and disinfecting agent such formaldehyde or glutaraldehyde, alcohol used to accelerate drying of some RMD. For this reasons, some national guidelines recommend to avoid use of this subtances or require specific precautions (for instance thorough cleaning)

“The WFHSS executive committee is pleased to put the WFHSS Guidelines at your disposal.
They have been written for all the professionals working directly or indirectly in the field of the reprocessing of Reusable Medical Devices (RMD) used in Health Care facilities.

They are the result of a consensus from a review of national practices, standards, regulations.
They are intended to provide guidance and the state of the art recommendations from an academic world society focused on science but their purpose is not to supersede local regulation, standards or guidelines.
They will be updated regularly to follow the evolution of the science and the evolution of the RMD and the technologies.

Your feedback is essential to contribute to the improvement of the Guidelines , feel free to use the form to send your comments or suggestions.

We wish you interesting reading!

On behalf of the Executive Committee

Dr Christine DENIS, President” 

Non terminal sterilization

Non terminal sterilization is a process whereby product is not sterilized in a sterile barrier system and hence not protected from environmental and handling contamination after the sterilization cycle.

Terminal sterilization

Process whereby product is sterilized within its sterile barrier system (ISO 11139 : 2018)

Standard operating procedures (SOP's)

SOP’s are written, step-by-step instructions that describe how to perform a routine activity. SOP’s aim to achieve efficiency, quality output and uniformity of performance, while reducing miscommunication and failure to comply with industry regulations.


For the needs of the present guidelines outsourcing means a process in which a healthcare facility employs another organization to perform some or all reusable medical device reprocessing tasks. The organization can be another healthcare facility, a shared reprocessing unit or a private service company. The services can be perfomed within the healthcare facility or externalized.


Pyrogen are substances that induces fever. Endogenous pyrogen are low-molecular weight protein produced by phagocytic leukocytes in response to stimulation by exogenous pyrogens. Exogenous pyrogens are produced by bacterial endotoxins and other microbial product such as antigen, antibody complexes, virus


Endotoxins are lipopolysaccharide components of the cell wall of Gram-negative bacteria that are heat stable and elicits a variety of inflammatory responses in animals and humans (ISO 11139: 2018)


Ability to trace the history, application, use and location of an item (products, parts, materials, and services) or its characteristics through recorded identification data.


For the purpose of theses guidelines, training means the certified acquisition of the theoricital, practical skills and behavior adapted to the assignment. Skills are periodically controlled and updated as needed.

Routine controls

Routine control check that performances of process or equipment are maintained over time between 2 process validations. Routine controls can be systematic (at each cycle) or at predefined periodicities. For instance, for the sterilization process, at end of each cycle, it is checked that process parameterare are within the validated tolerances, leak tests are performed daily or at periodicity defined by local recommandations. 

Go to process validation chapter →

Instruction for use (IFU)

Written indication provided by the manufacturer to ensure correct and safe use of a products (including but not limited to reusable medical device, reprocessing equipment and consumables). IFU of RMD include the instruction for reprocessing. IFU are also available for reprocessing equipment and consumables.   

Risk analysis

Identification and analyzis of potential issues that could negatively impact a given process. Risk analysis includes an evaluation of the consequence and likelihood. The issues with the more severe consequences and higher likelihood of occurence are addressed in priority. As needed measure are then to minimize the occurence or consequence. Methods are available to improve the reliability of the risk analysis. 


Storage concerns mainly sterile medical device. Storage of disinfected devices may be allowed by local regulation in defined conditions.


Transport includes:

  • The transfer of soiled reusable medical device from the point of use to the reprocessing site and
  • the transfer of the sterilized or disinfected RMD to the point of use.

Process validation

Process validation means establising, by objective evidence that a process consistently produces a results or product meeting its predeternined objective. Process validation applies to all steps of RMD reprocessing from point of use processing to storage. When equipments are used validation include their installation qualification (IQ), operational qualification (OQ) and performance qualification (PQ).
Process validation is perfomed before implementation of a new process or equipment (initial validation). Revalidation takes place periodically (usually each year) or after event justifying total or partial revalidation (change in the process, maintenance of equipments).

Waste management

Waste management groups all activities and actions required to manage waste including the collection, transport, treatment and disposal of waste together with monitoring of the waste management process. Instrument reprocessing waste are are solid (i.e., single use packaging, detergent or disinfectant empty bottles, cleaning brushes, possibly sharp devices), liquid (i.e., cleaning, disinfecting, rinsing solutions) or gazeous (i.e., sterilization, cleaning or disinfection effluent). Waste might be non hazardous, infectious, or toxic. Waste management regulation limits impact on environment and protects staff. Waste management rules are country dependent.


Traceability is the ability to trace the history, application, use and location of an item (products, parts, materials, and services) or its characteristics through recorded identification data.

Reusable Medical device (RMD) 

Medical devices wich are not single use i.e. which can be reused under appropriate reprocessing conditions, for an undelimited number of time or for a predetermined number of use.