FOI release

Freedom of Information request on use of ethylene oxide to sterilise swabs used in testing for Covid-19

Published 28 May 2021

28th April 2021 FOI 21/393

Dear

Thank you for your email of 10 April 2021 with your concerns on the use of ethylene oxide to sterilise swabs used in testing for Covid-19.

Please be reassured that the swabs are safe to use.

Ethylene oxide is a gas that is commonly used to sterilise many different types of medical devices, including swabs used in test kits.

The sterilisation process consists of a number of highly controlled and monitored stages, including removing ethylene oxide after treating the swabs. The amount of residual EO that is allowed has been set (by the international standard ISO 10993-7:2008) according to contact time of the medical device with the person. Contact time is divided into 3 categories: limited, prolonged, and permanent duration.

The swabs used in lateral flow test kits fall under the category of limited contact time. These limits are not further divided by body weight and therefore the limits set are also applicable for children.

These allowable limits were selected to ensure that any residual levels present on the medical device after sterilisation pose minimal risk.

The average time of contact for a single test (around 20 seconds) and the current testing regime (twice a week), means that each person is exposed to any residue on the swab for around 40 seconds per week. Calculating from the allowed residues, a person would need to be tested twice a week for over 40 years for the total contact time to be in a higher contact category. Therefore, the manufacturer’s original calculations that these swabs are in the ‘limited’ contact category are still valid for the current testing regime.

In the highly unlikely event that a swab does contain a residual amount above the allowable limit, the risk to the user is still considered to be very low.

As part of the sterilisation process the manufacturer must confirm, and document, that the residual EO level on a medical device is below the specified allowable limit before the device is packaged ready for use. The whole process is overseen by an independent, third-party organisations before a CE/UKCA mark can be placed on the medical device. The identifying number of the third party can be found next to the CE/UKCA mark symbol on the packaging of the swab.

If you disagree with how we have interpreted the Freedom of Information Act 2000 with regards to your request, you can ask for an internal review. It will be carried out by a senior member of the Agency who was not involved with the original decision. Internal review requests should be submitted within two months of the date you receive this response and addressed to: [email protected]. If you were to remain dissatisfied with the outcome of the internal review, you would have the right to apply directly to the Information Commissioner for a decision. Please bear in mind that the Information Commissioner will not normally review our handling of your request unless you have first contacted us to conduct an internal review. The Information Commissioner can be contacted online: https://ico.org.uk/make-a-complaint/official-information-concerns-report/official-information-concern/

Yours sincerely

MHRA Customer Service Centre

Medicines and Healthcare products Regulatory Agency 10 South Colonnade, Canary Wharf, London E14 4PU