Determination of sterilization residues by ETO according to ISO 10993-7

Industrials of the Health sector, you wish to verify the conformity of your devices to ISO 10993-7

What is ISO 10993-7?

Ethylene oxide and ethylene chlorate sterilization are widely used sterilization methods for their microbiological effectiveness. These sterilizations are used in particular for medical devices and pharmaceutical products that cannot withstand traditional high-temperature steam sterilization (such as single-use medical devices for example). Thus, the ISO 10993-7 standard “Biological evaluation of medical devices – Part 7: Ethylene oxide sterilization residues” is an international regulation related to the sterilization of finished products. It allows the determination of residues from ethylene oxide and ethylene chlorate sterilization of medical devices and verifies the maximum elimination of residues of these chemicals.

Why measure ethylene oxide sterilization residues according to this ISO standard?

This standard specifies the procedures for the determination of ethylene oxide and ethylene hydrochloride and the allowable limits (expressed as average daily patient dose (mg/day)) of these residues per device.

In addition, the ISO 10993-7 standard specifies the procedures and criteria for product release. As a result, three categories of exposure based on the duration of contact have been defined:

  • <24h, for limited contact,
  • <30 days, for prolonged contact,
  • > 30 days, for permanent contact.

Thus, in order to optimize your products according to the ISO 10993-7 standard, the support of a specialized laboratory is a considerable asset

FILAB supports you in the determination of ethylene oxide according to ISO 10993-7

As an expert in the field of trace organic substance analysis, FILAB assists you at every stage of the validation of your industrial processes, particularly sterilization processes.

Our specialists have developed specific methods for the determination of Ethylene Oxide and Ethylene Hydrochloride on medical devices, using exhaustive extraction to recover all residues.  The assay is performed by HS/GCMS (Headspace Injection followed by Gas Chromatography coupled to a Mass Spectrometer).

Nos spécialistes ont développé les méthodes de dosages spécifiques de l’Oxyde d’Ethylène et du Chlorhydrate d’Ethylène sur Dispositifs Médicaux, par extraction exhaustive afin de récupérer la totalité des résidus.  Le dosage est réalisé par HS/GCMS (Injection par Espace de Tête suivi d’une Chromatographie en phase Gazeuse couplée à un Spectromètre de Masse).

Did you know that?

On 10/09/2015, a health policy decision setting specific conditions for the marketing and distribution of certain medical devices sterilized with ethylene oxide was issued by the ANSM (National Agency for Health and Medicines):

The positive aspects of FILAB

  • A highly qualified team

  • Responsiveness in responding to and processing requests

  • A complete analytical park of 2100m²

  • Tailor-made support

Certification to the ISO 10993-7 standard demonstrates that the laboratory has met the criteria for safety, reliability, and quality in testing medical devices. The certification process ensures that the laboratory has the appropriate equipment, facilities, and personnel to conduct the testing in accordance with the standard's requirements.


In order to be ISO 10993-7 certified, each laboratory must follow the 7 following criteria:


  1. Quality Management System: The laboratory must have a documented quality management system that meets the requirements of ISO 17025 or ISO 9001.


  1. Competence of Personnel: The laboratory must employ personnel who are competent and have the appropriate education, training, and experience to conduct the testing.


  1. Equipment and Facilities: The laboratory must have appropriate equipment and facilities to conduct the testing in accordance with ISO 10993-7.


  1. Test Methods: The laboratory must use test methods that are appropriate for the medical device being tested and in accordance with ISO 10993-7.


  1. Quality Control: The laboratory must have a quality control system in place to ensure the accuracy and reliability of the test results.


  1. Reporting of Results: The laboratory must provide accurate and complete reports of the test results, including the methods used, data obtained, and any limitations or uncertainties associated with the test.


  1. Confidentiality: The laboratory must maintain the confidentiality of all client information, including test results and other proprietary information.

The European Union (EU) has specific legal requirements regarding ethylene oxide sterilization residuals testing for medical devices, which are outlined in the Medical Device Regulation (MDR) and In Vitro Diagnostic Regulation (IVDR). These regulations apply to all medical devices sold in the EU, including those that are imported from outside the EU.


According to the MDR and IVDR, manufacturers of medical devices must ensure that their devices are safe and effective. This includes demonstrating that devices have been appropriately sterilized and that any residual ethylene oxide or its by-products do not exceed the maximum allowable limits. The regulations specify the following requirements for ethylene oxide sterilization residuals testing:


  • Biocompatibility Testing: Medical device manufacturers must conduct biocompatibility testing of the device, including testing for ethylene oxide sterilization residuals. The testing must be conducted according to ISO 10993-7.


  • Maximum Allowable Limits: The MDR specifies the maximum allowable limits for ethylene oxide and its by-products, including ethylene chlorohydrin and ethylene glycol. The limits vary depending on the device type and duration of contact with the body.


  • Risk Assessment: Manufacturers must conduct a risk assessment to determine the potential risk to patients associated with any residual ethylene oxide or its by-products.


  • Sterilization Validation: Manufacturers must validate the sterilization process used for their device to ensure that it is effective in eliminating microorganisms and that residual levels of ethylene oxide and its by-products are within the allowable limits.

In Europe, medical device manufacturers are required to comply with regulations related to residual testing of ethylene oxide (ETO) as part of the biocompatibility testing of medical devices. If a manufacturer fails to comply with these regulations, there are several legal risks they may face:


  • Regulatory Action: If a medical device manufacturer fails to comply with the ETO residual testing requirements, they may face regulatory action from the competent authorities in Europe. This could include withdrawal of the device from the market, suspension or revocation of the CE marking, and fines.


  • Liability for Product Defects: If a medical device is found to have residual levels of ETO that exceed the allowable limits, the manufacturer may be held liable for any harm caused to patients. The manufacturer could face claims for damages resulting from product defects, including personal injury, loss of income, and other damages.


  • Reputational Damage: Failure to comply with ETO residual testing requirements could damage the reputation of the medical device manufacturer. This could lead to a loss of trust from healthcare professionals and patients and ultimately affect the company's bottom line.


  • Market Access: Medical device manufacturers that fail to comply with European regulations related to residual testing of ETO may be denied market access. This could affect their ability to sell their products in Europe and impact their financial performance.

Ethylene oxide (EO) sterilization is a commonly used method for sterilizing medical devices, but it does come with certain risks. To minimize these risks, it is crucial to implement appropriate measures, including proper validation, monitoring, and residual testing. Here are some key steps to minimize risks associated with ETO sterilization:


  1. Validate the ETO sterilization process and ensure it meets regulatory requirements.
  2. Perform material compatibility studies to ensure devices are compatible with EO.
  3. Properly prepare devices before sterilization, removing sensitive materials.
  4. Allow adequate time for aeration and degassing after ETO exposure.
  5. Conduct routine residual testing using validated analytical methods.
  6. Establish acceptance criteria for ETO residual levels based on safety guidelines.
  7. Document the sterilization process and maintain records for traceability.


Anaïs DECAUX Customer Support Manager
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