Reprocessing validation is a critical step in the lifecycle of reusable medical devices, allowing them to be used multiple times without posing a risk of infection to the patient. Cleaning validation, more specifically, refers to the process of ensuring that the device is sufficiently free of organic soil and other contaminants, either before use or before further disinfection and sterilization steps are performed, depending on the device.
This article summarizes EU and US FDA requirements for cleaning validation, from the types of medical devices that require testing to international standards the process is most often based on. If you have further questions about the topic or require reprocessing validation for your company’s products, do not hesitate to contact us.
The legal framework for cleaning validation
The obligation to conduct cleaning validation studies derives from regulations that require manufacturers to provide adequate instructions for the safe use of medical devices. The following parts of the EU Medical Device Regulation (MDR) and US Code of Federal Regulations Title 21 (21 CFR) are particularly relevant:
Section 23.4.n of Annex I of the MDR requires the manufacturer to provide detailed “information on the appropriate processes for allowing reuse, including cleaning, disinfection, packaging and, where appropriate, the validated method of re-sterilization” for reusable devices. The manufacturer must also provide information on how to determine when the device can no longer be used safely.1
Section 801.5(g) of 21 CFR requires manufacturers to provide adequate directions for use, including preparation for use, for the medical devices they bring to market. In a 2015 guidance document, the FDA states that it interprets this to include reprocessing instructions for reusable devices because they are “critical to ensuring that a reusable device is appropriately prepared for its next lay use and that licensed practitioners can use the device safely”.2
Categorization of medical devices for reprocessing validation
The stringency of the required reprocessing procedure depends on the classification of the reusable device. Devices are allocated into one of the following categories based on their potential for transmitting infections:3
Non-critical devices come into contact with intact skin or do not come into direct patient contact. Such devices include blood pressure cuffs, stethoscopes, skin electrodes, and the external parts of infusion pumps and ventilators.
Semi-critical devices come in contact with intact mucous membranes or non-intact skin, either directly or indirectly through breathing gas. Examples include endotracheal tubes, bronchoscopes, laryngoscope blades, diaphragm fitting rings, and gastrointestinal endoscopes.
Critical devices are directly introduced into the bloodstream or come into contact with normally sterile tissues. They include surgical instruments, laparoscopes, arthroscopes, and intravascular endoscopes.
Devices in all three categories require cleaning validation for safe reuse. In addition, non-critical devices can require disinfection validation, while semi-critical devices require either disinfection or sterilization validation. Critical devices must be sterilized before reuse, making sterilization validation mandatory.
Standards for medical device reprocessing and cleaning validation
The ISO 17664 standard family is commonly applied to medical device reprocessing validation under the MDR and FDA premarket submission processes. Part 1 (ISO 17664-1) outlines the procedure for critical and semi-critical devices, while Part 2 (ISO 17664-2) applies to non-critical devices. Both are harmonized medical device standards in the EU and FDA-recognized consensus standards in the US, although some sections of Part 1 are outside of the FDA’s scope of recognition.4
Other often-used technical information reports and standards include AAMI TIR12, AAMI TIR30, ANSI/AAMI ST98, and ANSI/AAMI ST81. The last is particularly relevant for US-based manufacturers, as the FDA directly recommends that medical device manufacturers refer to the latest version of AAMI/ANSI ST81 when developing reprocessing instructions.5
Defining the cleaning process
Before cleaning validation can be performed, the manufacturer has to formulate and document the cleaning process. This includes drafting comprehensive cleaning instructions for the device, accounting for its intended use and potential routes of contamination. The instructions should account for less-than-ideal situations, such as human error and the unavailability of automated cleaning technologies. According to ISO 17664-2, the instructions for non-critical devices should cover the following, when applicable:
Limitations on processing, specifying the number of times the device can be reprocessed or another way to determine when it can no longer be used safely.
Initial preparation before cleaning, including disassembly instructions.
Manual and/or automatic cleaning instructions, including specific parameters, such as cleaning accessories, process chemicals, water quality, and automated cleaning cycle type and duration.
Disinfection instructions listing appropriate process chemicals, accessories, and rinsing methods.
Drying method and maximum temperature.
Maintenance, inspection, and testing instructions for checking that the device remains functional after each cleaning cycle.
Packaging and storage instructions, including a description of appropriate protective covers or containers and maximum temperature and humidity of the storage environment.
In addition to these, the processing instructions for critical devices and most semi-critical devices will have to include a description of a validated sterilization procedure.
Cleaning validation study design
Once the cleaning procedure has been defined, a validation study is required to demonstrate that devices subjected to the procedure are consistently sufficiently clean to allow for further processing and eventual reuse. A typical study consists of the following steps:
Contamination with artificial test soil representative of real-life contaminants the device is likely to be exposed to.
Cleaning according to the manufacturer’s instructions.
Examination of results both visually and quantitatively. At least two quantitative test methods (e.g. total organic carbon (TOC) and protein content) appropriate for clinically relevant soil should be used.
The study design should incorporate a worst-case scenario approach, including the least rigorous allowable implementation of the cleaning process, the most challenging device configuration, and the greatest degree of foreseeable contamination.6
Our solutions for medical device reprocessing validation
Measurlabs offers cleaning validation studies conducted according to international standards, FDA guidelines, and EU MDR requirements. In addition, we can support manufacturers with disinfection and sterilization validation. The following are examples of our most popular standardized services in this area:
Please note that we can always tailor the testing procedure to suit your device, market area, and other requirements. Do not hesitate to contact us through the form below for an offer.
References
1 Section 23.4 of Annex I of Regulation (EU) 2017/745
2 See Section 801.5(g) of Code of Federal Regulations Title 21 and Part II. Background of FDA Guidance Document titled “Reprocessing Medical Devices in Health Care Settings: Validation Methods and Labeling”
3 More information on device categorization can be found in Annex E of standard ISO 17664-2:2023 and on pages 9–12 of the FDA Guidance Document on reprocessing validation.
4 Summary list of harmonized standards for medical devices is available on the European Commission’s website, while the FDA maintains a database of recognized consensus standards. See the Extent of Recognition section in the Supplementary Information Sheet for ISO 17664-1 for the parts the agency does not recognize.
5 Section V.B. Resources for Developing Reprocessing Instructions on page 6 of the FDA Guidance Document on reprocessing validation.
6 Section VIII. Validation of Cleaning Process in the FDA Guidance Document outlines the agency's recommendations for validation studies.