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Medical Device Sterilisation : Key Essentials, Options And Challenges

Importance Of Sterilisation


Ms. Divya Ganapathy
Technical Consultant- Medical Device Regulatory Services
UL India

Mr. Jan Peeters
Global Program Manager, Scientific Director & Primary Designated Engineer (PDE)
UL Germany

The sterilisation of medical devices (MDs) has become increasingly complex in order to prevent patient exposure to infections caused by organisms on instruments and devices used during treatment.

Inadequate sterilisation of MDs results in a significant increase of potential patient nosocomial infections and mortality/morbidity concerns. Beside patient health, it also increases costs for patient, healthcare institute and system. The industrial sterilisation techniques of MDs most often used worldwide are steam, ethylene oxide (EO), and gamma and electron beam irradiation. Further techniques are typically chemical sterilisation, such as low-temperature hydrogen peroxide gas plasma, low-temperature per acetic acid gas plasma, vapor-phase hydrogen peroxide, ozone and chlorine dioxide.

Sterilisation of medical devices is of the utmost importance in the medical field. Thousands of patients die every year or are infected with disease because medical devices were not properly sterilised. Complications after surgery are often the result of an improper sterilisation. Sterilisation of reusable medical devices is of the utmost importance to prevent the spread of diseases. If proper sterilisation was not practiced, a number of medical problems can occur. As evident, these problems can be simple or complex in nature. However, they are relatively simple to prevent. The growth and spread of diseases are just two of the most important reasons why medical devices must be sterilised before use. Bacterial spores are the most resistant of all living organisms because of their capability to withstand destructive agents. Chemical or physical processes used to destroy all pathogenic microorganisms, including spores on a medical device have their specific function. Nevertheless, if the sterilisation parameters of the sterilisation process meet those of the validation, the sterilised instruments, supplies and equipment are considered to be sterile.

The disinfection of reusable medical instruments is a frequently used practice. There is a significant difference between disinfection and sterilisation. Sterilisation is defined by ISO 17664 as a “process used to render a device free from all forms of viable microorganisms” whereas disinfection is defined in this standard as a “process used to reduce the number of viable microorganisms on a product to a level previously specified as appropriate for its further handling or use.”

Importance of Sterilization

Importance of Sterilization

Because disinfection is faster and less expensive, some hospitals substitute high level disinfection for sterilisation of medical instruments. An object should be disinfected and/or sterilised depending on its intended use. Critical reusable devices (those that are introduced directly into the bloodstream or which contact a normally sterile tissue or body space during use, such as laparoscopes, intravascular endoscopes and all endoscope biopsy accessories) require sterilisation before use. Semi-critical and non-critical devices that touch mucous membranes or intact and non-intact skin, like respiratory therapy equipment, and diaphragms, require at least a high-level disinfection. If a reusable device is only subjected to a high-level disinfection, it may not be labeled as “sterile.”

Sterilisation is categorized into high temperature sterilisation, chemical sterilisation and radiation sterilisation. Tables 1 and 2 summarize the various sterilisation techniques available within each category.

Validation And Importance:

As discussed above, only products going through validated processes are evaluated as being sterile. Therefore, process validation is important for the safety, reduction of variation in results and greater confidence in the reliability of results and is necessary in view of quality assurance of sterilisation and disinfection, regardless of technique. It must be performed systematically and should include all systems, facilities and processes. The validation should demonstrate that they perform adequately and consistently as specified. The complete validation must be documented. A validation confirms that the processes have been properly developed and are under control. It demonstrates a high degree of assurance that uniform products will be produced over a longer period of time that always meets the predefined specifications.

The advantage of a validation is to receive a better understanding of processes and thus streamline the processes. It decreases the risk of regulatory non-compliance and requires less in-process controls and end product testing. Validation should be considered for all processes, especially when using new processes and equipment is used. Re-validation should be considered when processes and equipment have been altered to suit changing priorities and where the product test has a poor and unreliable indicator of quality.

Importance Of Sterilisation

Process validations are typically completed prior to the release of the finished product (prospective validation). In case this is not possible, it may be necessary to validate processes during routine production (concurrent validation). Non-validated processes, which have been in use for some time without any significant changes, may also be validated according to an approved protocol (retrospective validation).


Medical Devices can be sterilised using various techniques. Depending upon the materials used as well as the availability of the sterilisation technique, a certain sterilisation technique should be chosen. However, first after subjecting single-use and reusable MD to validated sterilisation processes the products can be used as sterile products and thus increase patient safety.

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