Can Benchtop Autoclaves Speed Up Medical Device Lifecycle Testing?

Why Is Medical Device Testing Essential for Approval?

Medical device testing is an essential process that must be performed by all the manufacturers worldwide to ensure the effectiveness, safety and performance of their device. To satisfy the European Union’s Medical Device Regulations EU(MDR) 2017/745 (including the United Kingdom) the device manufacturer must provide evidence and comprehensive documentation of testing. In the United States of America (USA) the requirements are stipulated by the Food and Drug Administration (FDA). The regulatory body through which approval is sought will depend upon the market. However, whichever route is chosen evidence of testing will inevitably be required. This testing is usually performed at medical device testing laboratories. Often these laboratories will specialise in a specific area of testing.

What Role Does Lifecycle Testing Play in Medical Device Approval?

Testing laboratories require technical expertise and specialist equipment which adds to the financial cost of testing. Furthermore, time is an important factor and anything that can accelerate the process without unduly increasing the cost pressure is beneficial, therefore small companies offering bespoke testing may be more agile where rapid turnaround times are required. 

Medical device stability/accelerated aging and product lifecycle testing provides information on how the device will be unaffected by environmental conditions such as heat and humidity. Over a period the physical/chemical/functional properties of both sterile and non-sterile devices can change or be compromised.

Under the MDR medical device stability testing should be an integral part of product verification and validation and the results included in the technical file required for CE (Conformité Européene) certification in Europe, and CA (Conformity Assessed) certification in the United Kingdom. Currently the CA Certification is not recognised in Europe, although the CE certification is still accepted in the UK.

In the USA approval to market a new device comes from the Food and Drug Administration and the rout depends upon the type of device, Pre-Market Notification (510K), Pre-Market Authorisation (PMA) and De Novo classification.

Although some surgical instruments are moving to single use designs, for those reusable devices during their lifetime in clinical use these products will be sterilised using an autoclave multiple times. 

Dental micromotors, for example, can have a design life of 1,000 autoclave cycles and so accelerated testing must be performed to confirm this.  Dental handpieces are Class II medical devices according to the FDA and therefore subject to 510k.  Other surgical hand tools may have a design life up to 3,000 autoclavable cycles.  

Can Benchtop Autoclaves Improve Lifecycle Testing Efficiency?

Medical device stability/accelerated aging and product lifecycle testing can be performed using a benchtop autoclave. However, it is also necessary to monitor the environmental conditions in real-time. The autoclave chamber where the medical device (load) is sterilised is subject to steam, high temperature, high pressure and vacuum during the program cycle. To cope with this environment the chamber is usually constructed from 316L grade stainless steel.

A type ‘B’ autoclave is most commonly used to sterilise surgical instruments. “B-type autoclaves feature a vacuum pump to pull the air out of the chamber. Their ability to sterilise porous materials and hollow instruments makes them a preferred choice in healthcare, laboratory and veterinary settings” (Brown, S, 2024).

There is a range of sterilisation cycles (programs) available on a benchtop autoclave but for surgical instruments the 134°C Prion B program would be the most appropriate (see Figure 1). The cycle time for this program is typically 32 minutes, although this may vary slightly between manufacturers. This does not include the loading time. 

Furthermore, benchtop autoclave manufacturers will recommend a pause period between program cycles of up to 20 minutes. Omission of this pause period runs the risk of accumulating water vapour in the chamber from the water storage tank. The program length and pause cumulative time make performing accelerated testing of 1,000 or even 3,000 cycles an arduous task and very time consuming. For the 1,000 cycles this would take more than one hundred days based on an average working day.

Some benchtop autoclaves on the market have the facility to customise programs which can reduce the testing time significantly and can prove extremely beneficial. 

Figure 1 – Class B autoclave sterilisation cycle

What Conditions Must be Monitored Inside an Autoclave Chamber?

Routine testing is performed on autoclaves by owners to ensure that the set temperature and pressure in the chamber during the autoclave cycle are maintained to safeguard correct sterilisation of the load (medical device under test). To provide assurance that an autoclave is functioning correctly a steam penetration test should be performed daily and the results recorded in the autoclave logbook. These tests can be thought of as Quality Control (QC) and there are two types of steam penetration tests available: Bowie-Dick or Helix. 

The Bowie-Dick test was first developed in 1963 its purpose is to determine the efficacy of steam penetration on large porous loads.  Subsequently the Helix test was introduced in around 2009, but it is more stringent as it is designed to detect the effectiveness of air removal and steam penetration of hollow instruments.

Conducting a steam penetration test daily enables users to verify the sterilisation processes are being performed correctly by the autoclave. It is also a useful early indicator of problems with an autoclave.  Each autoclave should have its own logbook detailing the steam penetration test performed and any maintenance undertaken. 

For accelerated aging and lifecycle testing we need to take this a step further and measure the environmental conditions within the autoclave chamber continually throughout the cycle as sporadic testing with a penetration test cannot give this level of assurance. 

Using a Class B autoclave (with vacuum) permits testing to BS EN 13060:2025 standard. Measuring environmental conditions, temperature, humidity and pressure within an enclosed chamber could pose a challenge. Fortunately, autoclaves are all fitted with a test port which is used as part of a routine technical service to verify that the temperature achieved in the chamber corresponds to the program set. As part of servicing a temperature probe is inserted to a port in the chamber. This port may be in the door as shown in Figure 2 or in the wall of the chamber.  This port can also be used to connect hermetic feedthroughs which enables wires to be connected through the wall of the chamber whilst still enabling the autoclave to work normally. This permits sensors to be placed within the load and around the external of the load within the chamber and connected to an external multi sensor datalogger.

Figure 2 – Temperature probe port in the door

How Can Dataloggers Enhance Autoclave Testing Accuracy?

Multiple sensors can be connected to the datalogger through a hermetic feedthrough in the chamber test port to collect data variables. The datalogger overcomes the laborious and tedious need for human intervention to manually record variables and furthermore the potential for human error.

Dataloggers eliminate these limitations by continuously and accurately recording data in an internal memory at predetermined intervals, allowing for a subsequent comprehensive and detailed analysis of the data variables from the sensors. The data can then be presented in a variety of ways including such as graphs or charts whilst retaining the raw data for statistical analysis if required. 

Why Are Benchtop Autoclaves a Practical Choice for Small Labs?

When brining a new medical device to market, especially those requiring sterilisation, stability and lifecycle testing is a key requirement in seeking regulatory approval. Benchtop autoclaves used in conjunction with sensors connected using hermetic feedthroughs to a data logger can provide an efficient and reliable way of collecting the required data. Small test labs may be more agile when rapid results are required and customisable programmes in the autoclave can reduce the testing time even further. 

References

British Standards Institution (2025) BS EN 13060 Sterilizers for medical purposes. Small steam sterilizers. Requirements and testing. London: British Standards Institution.

Brown, S. (2024) Is your autoclave safe? Putting frameworks in place for optimal performance and legal compliance. British Veterinary Association: In Practice 46(8): 449 – 452

European Parliament and the Council of the European Union (2017) Medical Device Regulations (EU) 2017/745. Official Journal of the European Union. Available from: https://www.medical-device-regulation.eu/?m=pc [Accessed 19.09.2025]

Disclaimer. The views and opinions expressed in this article are solely those of the author and do not necessarily reflect the official policy or position of Test Labs Limited. The content provided is for informational purposes only and is not intended to constitute legal or professional advice. Test Labs assumes no responsibility for any errors or omissions in the content of this article, nor for any actions taken in reliance thereon.