A PROBLEM SHARED

Dr Ranj is always here for you

We’ve started using lateral flow tests for COVID at work. I’m a bit worried because someone told me they contain ethylene oxide, which is known to cause cancer. Is this true?

Up until recently, the only way to diagnose someone with COVID was to do a PCR swab, where a swab of the nose and/or throat is used to pick up traces of coronavirus DNA. It is a highly sensitive test, but it can take several days to get a result.

Lateral flow tests (LFTs) are on-the-spot COVID tests, which can give you an answer within 30 minutes – and that means they are really useful from a practical point of view. However, the downside is that they are not as accurate as PCR tests. What they are very good at, though, is picking up people who are likely to be highly infectious, even if they don’t have symptoms, and this is precisely what we need to know if we want to limit transmission.

Much like anything to do with COVID, there have been some conspiracy theories coming out of the woodwork and circulating about LFTs, too.

It’s true that the swabs used may be sterilized using ethylene oxide. This is a gas that is used to sterilize objects that would otherwise get damaged during more routine sterilization procedures (such as heating to high temperatures).

Ethylene oxide is a colourless gas with a slightly sweet smell. It is known to damage DNA – which is why it is employed as a sterilizing agent – and can be dangerous if inhaled in large quantities. This is also why there are strict regulations around its use and exposure to humans.

Even though it may be used to sterilize LFT swabs, the gas breaks down rapidly afterwards. By the time the swabs get to you, there is either no trace of it at all, or any that remains is negligible – which means it cannot cause you any harm whatsoever. If it was a significant issue, it would damage the viral DNA which the tests are designed to detect, rendering them useless.

In conclusion, I don’t think you need to worry about the

LFT tests causing you any harm. What is more important is knowing how to use them properly and ensuring that you act on the result.

We need every tool we have at our disposal to escape the pandemic and return to normal life as soon as possible – and rapid testing will likely play a big part.

“By the time the swabs get to you, there is either no trace, or any that remains is negligible”