Experts warn that there could be a problem with lateral flow testing, which can detect Omicron cases daily in the thousands.
Chiefs of health insist that rapid kits which can detect the variant in 15 minutes or less are just as effective.
However, scientists claim that Omicron’s widespread spread is so extensive that many infected Britons have been misled into believing they are positive.
Free tests form a crucial part of Plan B at No10. Vaccinated contacts with positive cases are told to make use of them for seven days instead of isolating. To be allowed into football stadiums, people who have not been vaccinated must provide proof that they had a negative test.
Officials also advised the public that they use the kits in advance of Christmas to help stop the spread Omicron.
However, real-life evidence has shown that the results of these tests can only be obtained online and at pharmacies.
Omicron spreading rapidly across Britain with over a million lateral streams per day, this could mean that false positives are being given to thousands.
Ministers are concerned that the strain is spreading to as many people as possible, with London being its main focus.
A microbiologist from the University of Reading Dr Simon Clarke said that negative results are not proof of a person being infected.
According to the current level of swabbing across England, even a 1 percent false negative rate can lead to false diagnosis of virus-free status for thousands.
Many Britons complained that they were negative for lateral flow tests, but were told by PCR that their results are good.
And one A&E doctor in London claimed he tested negative after using a lateral flow test that told him to only swab his nose. He was however positive when he performed the same test on his throat to get a sample.
This comes after thousands have been unable to obtain the test this week due to the government repeatedly stopping order placements. On some days, the supply of chemicals has even run out.
MailOnline was told by experts that positive cases will be missed and they advised people to not test for Omicron infections too frequently in times of shortages. Experts warn that lateral flow testing is not as reliable as PCR. These tests require a longer turnaround time and can pick up Omicron cases faster.
LATERAL FLLOW TESTING: Yesterday, 1 million lateral flow tests took place in the UK. This is the highest number since January 6, (1.2million).
Orders for lateral flow tests were stopped by the government website, which was down intermittently. Meanwhile, thousands of pharmacies had run out. On Wednesday, however, the tests were still available.
Officials claimed there are many test options and that they had entered into new arrangements with Amazon and Royal Mail in order to provide more testing to customers at their homes.
People who don’t have symptoms should not take lateral flows. Those with no signs or symptoms are advised to get a PCR. This is followed by an analysis by laboratory technicians.
The UKHSA has preliminary evidence that lateral flow testing are just as effective in detecting Omicron than they were for Delta. The UKHSA will soon publish information on efficacy rates.
Fears were raised when a South African expert raised alarm over the super-variant and warned that lateral flow was less sensitive than Omicron.
Chairperson of South African Medical Association Angelique Coetzee stated to MPs on Science and Technology Committee, “The rapid test still shows false negatives during the early periods.
“We have many patients who wait for a week with a headache, then do PCR to confirm it.
Ministers were told by Dr Susan Hopkins that positive tests will be performed for both people with symptoms and patients without them.
She stated to MPs that they have been in use for nearly a year now.
“What we do know is that it will detect approximately 50% of all cases, but that it will also detect around 80% of those who are high-risk of transmitting the virus to others.
She said: “Again, public health advises to take an lateral flow before going out to socialise right now, and we would recommend it.”
MailOnline was informed by Dr Clarke that a negative test can indicate someone’s likelihood of being negative but is not proof.
Although he said that it was better to have close contact with positive cases than daily lateral flow testing, this would still leave many people at home.
Clarke stated that the tests would reduce the spread of the virus to infected persons, but not eliminate it.
Chris Stables, a Twitter user said that lateral flow tests showed he was positive for three days following a positive PCR test.
‘[The virus is]Spreading false positive lateral tests that people believe there are negative,’ he stated.
Ruske, British DJ, posted that he’d taken three lateral flow test, with two being negative and one being positive.
GP DR Helen Salisbury also warned Omicron was’spreading like wildfire and may infect people even with negative lateral flow testing’.
Olympia Campbell claimed that 10 tests she took in the past four days were negative and that a subsequent PCR showed she was positive.
Ryan Williams posted on the social media platform, saying he was positive for a test of PCR and negative on three lateral flow testing. [the virus] early’.
MailOnline was informed by Dr Alexander Edwards of Reading University who is an expert on biomedical technology. He said it was difficult to determine how efficient lateral flow tests can be in slowing down the spread.
He explained that although they do not work perfectly, they are very efficient and have a great deal of speed.
“So long as they understand they won’t always be able to pick up all the cases, I believe they can be very helpful.
‘The exact accuracy has been measured in a range of settings, and doesn’t seem ideal — lateral flow tests definitely miss some PCR-positive people.
‘But as a trade-off, daily testing with a slightly less accurate test vs less regular testing with a far slower — yet more sensitive — PCR test may turn out to be more effective.’
He noted that alternative — vaccinated close contacts of Covid cases having to self-isolate — is inconvenient and can cause many who are unable to work from home to lose earnings.
Dr Edwards advised people that they should only test when absolutely necessary, rather than as often as possible.
MailOnline spoke with Professor Lawrence Young of Warwick University. He said that Omicron tests were a “great tool” for stopping the spread of Omicron. Studies have found that they can pick up as much as 90% of Omicron-infected individuals.
He stated that the Flowflex kits are easy to use. They rely on a nasal swab, which is easier than taking samples of the throat and mouth.
“Of course, there’s a chance that infected people will not be found but this was not possible a year ago. Having a real-time test without the delays caused by PCR is very valuable.”
Professor Young added: ‘My mantra is “flow before you go” – we must encourage the responsible use of LFTs before people go out to mix with others.’
