People who feel unwell or are displaying Covid-19 symptoms are being urged not to take lateral flow tests.
The rapid tests, which produce a result in just half an hour, are being used to detect asymptomatic cases in certain population groups, including school-age children.
But there are concerns over the way they are being used, following reports of an increasing number of parents in Wiltshire using the home test kits for children who are feeling poorly.
This could lead to positive cases potentially being missed, increasing the risk of the virus spreading.
The rollout of rapid tests
Lateral flow tests were a key part of the Government's plan to reopen all schools, with pupils in secondary schools and colleges in England being tested by staff during the first week.
Back then, students who tested positive with a rapid test were not require to take a confirmatory PCR.
However, now that children are being tested at home, any lateral flow device that comes back positive has to be followed up with a lab-processed test.
This only applies to children who are asymptomatic, though, recently, some parents have been using them to test children with symptoms.
Kate Blackburn, Wiltshire Council's director for public health, said: "We are seeing an increasing number of situations where parents are using the lateral flow devices when their children are feeling unwell or if they are displaying Covid symptoms.
"Now, it's really, really important that lateral flow devices are not used for anyone - staff, pupils or parents - if they're displaying symptoms.
"If you or your child are displaying any of the Covid symptoms - a continuous cough, a high temperature, a loss or change in the sense of taste or smell - you must self-isolate and book a PCR test as soon as possible."
Rapid tests 'not meant for those with symptoms'
According to the public health boss, lateral flow tests were originally designed to test people with symptoms.
However, "the way they are being used in national policy is very clearly for asymptomatic individuals," she said.
The reason behind it goes back to the importance of self-isolating as soon as people start feeling poorly.
Mrs Blackburn explained: "What we're seeing is the possibility of people thinking 'I've got a lateral flow test, I will just have a quick check' and [if the test is negative] that crucial self-isolation of a household in those early stages before you get a confirmatory PCR test can be missed.
"I know it's confusing but it's just really important that if you are showing any symptoms, self-isolate straight away and get yourself a PCR test."
Who is eligible for lateral flow tests?
As it stands, adults living with primary, secondary and college-age children can get tested twice a week.
This also applies to adults in their childcare or support bubbles.
You can check your options to access rapid tests here.
University students, those working in small businesses who cannot work from home and early years staff and childminders are also eligible.
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