Amazon (AMZN), eBay and Wish have removed a number of blood oxygen testing devices from their platforms after concerns that the products were not legally fit for sale in the UK.

According to Which? 11 out of 15 cheap pulse oximeters bought from online marketplaces, for as little as 99p, failed to comply with UK and EU law when it assessed them.

One product being sold via the online marketplaces was missing its CE mark completely, while others had CE marks that failed to comply with Medicines and Healthcare products Regulatory Agency (MHRA) guidance on required markings for a medical device.

The consumer champion also found that some of the products were falsely claimed to be NHS-approved. They were found to have NHS wording or the logo to look more legitimate, which could potentially be a breach of consumer protection law.

The products were also featured prominently in search listings, had lots of reviews, Which? said.

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It comes as pulse oximeters have become increasingly popular since the COVID-19 pandemic began. They measure oxygen levels in the blood which can drop to dangerously low levels without the patient noticing, in what is known as "silent hypoxia".

Pulse oximeters are being used by the NHS to assist vulnerable patients with home monitoring of COVID or post-COVID symptoms. Patients may be given a pulse oximeter by their GP.

A Department of Health and Social Care spokesperson told Which?: “The NHS does not approve or endorse any medical devices, including oximeters.”

When Which? notified the online platforms about the incorrect certification on the products it found, they took them down, although five devices had already disappeared from sale before they were contacted.

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However, since the initial investigation, Which? found more ‘NHS-approved’ pulse oximeters being sold on Amazon and eBay. Amazon even sent marketing emails to Which?’s researchers, promoting ‘NHS-approved’ pulse oximeters.

The group added that all of the pulse oximeters it tested did pass its accuracy tests without any major issues, able to measure the blood oxygen saturation of each of Which?’s panel with an acceptable error margin.

“However, buying from an unknown seller could come with risks, as the high number of uncertified models shows,” Which? warned. “It can be a lottery for consumers to know what they are getting and other snapshot tests Which? has done, such as digital thermometers, have uncovered products that can give inaccurate readings.”

It is calling on the government to do more to increase checks on products being sold online, asking them to bring in tougher laws and regulations to make online marketplaces legally responsible for ensuring the safety of products offered through their sites.

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“It is very concerning that our investigation found these medical devices for sale without the required safety markings or brazenly claiming to be approved by the NHS - and the biggest online marketplaces were not picking up on these red flags,” Natalie Hitchins, Which?’s head of home products and services, said.

“Which? believes the government needs to do more to protect consumers from a lack of effective safeguards when they are shopping online by bringing in tougher regulations for online marketplaces.

An Amazon spokesperson said: “Safety is important to Amazon and we want customers to shop with confidence in our stores. We have proactive measures in place to prevent suspicious or non-compliant products from being listed and we monitor the products sold in our stores for product safety concerns.

‘When appropriate, we remove a product from the store, reach out to sellers, manufacturers, and government agencies for additional information, or take other actions.

‘If customers have concerns about an item they’ve purchased, we encourage them to contact our customer service directly so we can investigate and take appropriate action.”

Ebay and Wish also responded, both confirming that they had removed listings necessary.

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