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Medical Device, Microbiology

Device Cleaning and Disinfection Validations – A Primer


Scientific advances in both diagnostic and therapeutic medicine have led to the development of new and sophisticated reusable medical devices and instruments for use by health care practitioners and for home/ personal use as well. Manufacturers of reusable medical devices have the responsibility to support product label claims of reusability by providing complete and comprehensive written instructions for the handling, cleaning, disinfection, testing, packaging and aeration for the product between each use. Label instructions for reuse require validation for FDA compliance in order to ensure proper and safe reprocessing of the devices by health care facilities, and validation of the recommended cleaning/disinfection instructions is required prior to labeling the device for reuse.

The FDA places the primary responsibility on the manufacturer for developing and validating methods for effective reprocessing of reusable medical devices. Not only is proving cleaning and disinfection efficacy necessary, but function, physical integrity, and biocompatibility issues may need to be addressed as well. Choosing a validation process for reusable devices should rely on guidance from the FDA and validation methods developed by AAMI, as well as International Standards (ISO, ANSI).

Cleaning Efficacy Tests and Validations

Cleaning is the first critical step in reprocessing reusable medical devices. Cleaning methods are divided into two categories: manual and mechanical/automated. Reuse instructions require validation of the methods in order to assure proper and safe reprocessing of the devices by health care facilities.

The efficacy of the cleaning instructions will be based on the presence of markers that have been used to soil the device before cleaning.  The most common markers are protein and hemoglobin, but carbohydrates, TOC and endotoxin can also be used.  These markers should be below predefined concentrations after the cleaning is performed.

Types of Cleaning Tests and Validations

  1. Manual Cleaning – a documented, validated, and reproducible procedure for effective device cleaning that involves a combination of hands-on-wiping, brushing, and or flushing using validated cleaning solutions, and yields a device that is safe for use or ready for additional processing dictated by the device intended use. This type of method is prescribed when mechanical units are not available or instruments are too fragile or difficult to clean with a mechanical unit. It is often recommended for delicate or complex medical devices (microsurgical devices, lensed instruments, flexible endoscopes, and air powered drills).
  2. Mechanical (automated) Cleaning – a documented, reproducible automated or semi-automated cleaning procedure that is validated for use with medical devices and yields a device that is safe for use or ready for additional processing as defined by its intended use. A method of removing soiling and microorganisms through an automated cleaning and rinsing process, this includes ultrasonic cleaners and washers. Some types of equipment incorporates thermal disinfection processes and/or chemical disinfectant rinses capable of destroying various numbers and types of microorganisms.
  3. Ultrasonic Cleaning Methods – these provide the most effective means of removing soil from some medical devices. These methods are designed for fine cleaning of medical devices, used to remove soiling from joints, crevices, lumens and other areas that are difficult to clean by other methods.
    • Manual cleaning with sonication- combination of device cleaning by hands and ultrasonic cleaning.
    • Mechanical (automated) cleaning and disinfection with sonication- combination of automated and ultrasonic cleaning.
  4. Cleaning Verification Test – a test method that verifies the cleanliness of specific devices after manual and/or automated cleaning is completed. These verification tests are part of continuous quality improvement to demonstrate continued compliance with expected cleaning benchmarks. Many options are available to visualize or quantify the amount of residual test soils and cleaning reagent residuals remaining on cleaned devices. One can measure the presence of proteins, carbohydrates, hemoglobin, TOC or endotoxin.

Disinfection Efficacy Tests and Validations

Disinfection is performed by manually soaking a device in a container with a liquid chemical germicide solution (regulated solely by the FDA, solely by the EPA or by both agencies) or it can be accomplished using automated equipment such as washer-disinfectors. The most frequently used chemical disinfectants contain agents like glutaraldehyde, chlorine compounds, quaternary ammonium compounds, phenols, ortho-phthalaldehyde and hydrogen peroxide.

Some factors considered in the selection of a chemical disinfectant for a particular application include device compatibility with the chemical and category of the device to be disinfected (devices are classified into critical device, semi-critical device, noncritical device or environmental surfaces determined by the device’s intended use). How the device will come in contact with the patient, the physical configuration of the device, the type and degree of contamination after use, the physical and chemical stability of the device, and the ease or difficulty in removing the chemical agent after the necessary exposure time should also be considered in the selection of a chemical disinfectant.

Types of Disinfection Tests and Validations

  1. Chemical Disinfection (immersion method/ spray method/ wipe or swab method)
    • Low-level Chemical Disinfection (environment surfaces, non-critical devices) – a process that kills most vegetative bacteria, some viruses and some fungi, but not mycobacteria and bacterial spores.
    • Intermediate-level Chemical Disinfection (non-critical, semi-critical devices) – a process that kills viruses, mycobacteria, fungi and vegetative bacteria, but not bacterial spores.
    • High-level Chemical Disinfection (semi-critical devices, critical devices) – a process that kills all microbial organisms but not necessarily large numbers of bacterial spores.
  2. Thermal Disinfection – application of hot water to decontaminate reusable medical devices. Thermal disinfection selectively destroy microorganisms, and the level of decontamination achieved depends on the exposure time and exposure temperature. Thermal disinfection employs hot water temperatures of 60°C to 95°C (140°F to 203°F)
    • Short exposure time with high temperature
    • Long exposure time with low temperature

Outsourcing Your Cleaning and Disinfection Validations

Advancement in diagnostic and therapeutic medicine has led to more sophisticated medical device designs. As these designs become more complex, the process of adequately cleaning and disinfecting and/or sterilizing instruments has become more complex as well. Pacific Biolabs helps manufacturers in the validation of their product claims, and helps ensure patient safety by providing assurance that the product meets FDA requirements. PBL offers a wide range of selections from protocol preparation to validating and performing the routine cleaning and disinfection procedures. PBL will not only validate a given procedure, but will help in designing and creating protocols for a given device.

For a consultation on what is necessary for your device, please visit the Pacific BioLabs website for more information on cleaning and disinfection validation services, and we will also be happy to provide you with a quote on pricing for your specific project.

Pacific BioLabs