Antibody tests are back on the market in Superdrug

Britons can now buy coronavirus antibody tests on the high street to find out if they have had Covid-19 in the past. 

Superdrug has today relaunched its blood testing service after having it shut down by regulators in May over accuracy concerns.

The retailer changed its service to take blood from veins instead of relying on finger-pricks, which officials say isn’t proven to be accurate.

The tests, which cost £89 each, use kits developed by the company Abbott, which supplies the most accurate antibody test currently used by the Government. 

Twenty-eight Superdrug clinics around the UK have nurses trained to draw blood so it can be analysed to look for signs of past Covid-19 infection. But the retailer is not selling the kits as a walk-in service and customers must register online first.

Because nurses now have to take blood instead of people doing it at home, because of Government rules, the test costs £20 more than it did in May, when it was £69.

Millions of people across the UK are known to have had Covid-19 but never actually tested positive for it because the Government rationed swab testing during the peak of the outbreak. Many don’t know for sure if they have had the virus. 

A positive test result does not mean the person cannot catch the virus again and the Government isn’t offering the public antibody tests because it doesn’t want to confuse people.

The Superdrug tests take around three days to produce a result and are claimed to be 97.5 per cent accurate at spotting who has had the virus, although Public Health England evaluations found the accuracy is more like 93 per cent. 

Superdrug must now take vein blood samples for antibody tests after the Government regulator banned companies from offering tests done using finger-prick blood (stock image)

Superdrug must now take vein blood samples for antibody tests after the Government regulator banned companies from offering tests done using finger-prick blood (stock image)

Healthcare director at Superdrug, Michael Henry said: ‘People still want easy access to a service where they can find out if they have already been infected with Covid-19.

‘Launching this nurse-led antibody testing service in our health clinics gives them the choice to find out. 

‘Receiving a positive antibody test result does not however confer immunity, and it’s important that people understand that it does not mean you can be any more relaxed with the required hygiene and social distancing measures as set out by the government.’

WHAT IS AN ANTIBODY TEST AND WHAT IS IT USED FOR? 

Antibody tests are ones which look for signs of past infection in someone’s blood. 

Antibodies are substances produced by the immune system which store memories of how to fight off a specific virus. They can only be created if the body is exposed to the virus by getting infected for real, or through a vaccine or other type of specialist immune therapy.

Generally speaking, antibodies produce immunity to a virus because they are redeployed if it enters the body for a second time, defeating the bug faster than it can take hold and cause an illness. 

An antibody test, which involves analysis of someone’s blood sample, has two purposes: to reveal whether an individual has been infected in the past and may therefore be protected against the virus, and to count those people.

Knowing you are immune to a virus – although whether people actually develop immunity to Covid-19 is still unknown – can affect how you act in the future. Someone may need to protect themselves less if they know they have been infected, for example, or medical staff may be able to return to work in the knowledge they are not at risk.

Counting the numbers of people who have antibodies is the most accurate way of calculating how many people in a population have had the virus already.

This can be done on a small sample of the population and the figures scaled up to give a picture of the country as a whole.

In turn, this can inform scientists and politicians how devastating a second outbreak might be, and how close the country is to herd immunity – a situation in which so many people have had the virus already that it would not be able to spread quickly a second time.

Experts believe that around 60 per cent exposure would be required for herd immunity from Covid-19, but the UK does not appear to be anywhere close to that.

Early estimates suggest 17 per cent of Londoners have had the virus, along with five per cent of the rest of the country – about 4.83million people.

This means the virus might spread slightly slower in future but the risk of second outbreak and hundreds or thousands more deaths remains very real. 

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Antibody tests have been a controversial subject for months after the Government first pledged them to the public in March but rowed back on its decision.

Many tests turned out to be inaccurate and even if results are accurate, scientists still aren’t sure how to interpret them because people may not develop immunity.

The tests work by screening a small blood sample to look for antibodies, which are disease-fighting substances made by the immune system that are specific to one illness.

If Covid-specific antibodies are present in someone’s blood, it means they have been infected with the virus in the past and fought it off. 

Superdrug’s service requires someone to visit a clinic where a nurse will extract their blood from a vein in their arm and then hand them a stamped envelope.

The customer must then post their own blood sample in a special priority post box set up by Royal Mail, from which it will be taken to a laboratory for analysis.

The results are then analysed by a doctor and returned within two to three days, the company says. 

The new service comes after Superdrug’s first antibody testing service was shut down by the Medicines and Healthcare products Regulatory Agency (MHRA).

In May, the government agency told all companies to stop offering antibody tests to people using blood taken from their fingers at home.

Abbott, the American company that made the tests, had not approved them for use with finger-prick blood, it emerged, and regulators became concerned about their accuracy.

An MHRA spokesperson told MailOnline at the time: ‘Patient safety and public health are our main priorities and it is in the interests of everyone for antibody tests to be as reliable and meaningful as they can be.

‘There are several UK providers of testing services who offer Covid-19 antibody testing using a finger-prick sample of capillary blood collected in a small container.

‘We are asking all providers of laboratory-based Covid-19 antibody testing services using capillary blood collected by a finger-prick to temporarily stop providing this service until home collection of this sample type has been properly validated for use with these laboratory tests.

‘Use of unvalidated sample types may lead to unreliable results and as such we are working closely with the service providers, laboratories and test manufacturers to resolve the regulatory and patient safety issues.

‘People who have purchased one of these sampling kits, and received an antibody test result, should not consider the result to be reliable and should not take any action on it.

‘This does not affect rapid point of care tests or laboratory tests performed using venous blood.’ 

Blood from capillaries, because it comes through a wound in the skin, is more likely to be contaminated by the time it reaches the lab.

Tissue fluid from parts of the body surrounding the blood vessels, or substances on the skin, may mix with the tiny amount of blood and make it more difficult for the test to filter it accurately.

Taking the blood properly is key – for example, the first drop of blood should not be used for the above reason – and unqualified people might be less likely to get a clean sample if doing it by themselves.

The MHRA said those types of tests had never been approved in the UK but that it was acting after receiving reports that they were going on.  

Superdrug uses a testing kit developed by pharmaceutical firm Abbott, which has so far proven to be the most accurate laboratory test used by the UK Government

Superdrug uses a testing kit developed by pharmaceutical firm Abbott, which has so far proven to be the most accurate laboratory test used by the UK Government

Superdrug uses a testing kit developed by pharmaceutical firm Abbott, which has so far proven to be the most accurate laboratory test used by the UK Government 

It would use enforcement action to stop companies offering them if they did not follow the rules, the MHRA said. 

When Superdrug first launched its antibody testing service in the spring it experienced huge demand and had to suspend the process just hours after opening it because so many people booked tests.

The reason it is a popular service is that only 295,000 people have been officially diagnosed with coronavirus but approximately 2.8million have had it.

Office for National Statistics testing in the population suggests that 6.3 per cent of the population of England would receive a positive antibody test result.

This is equal to about 2.8million people, meaning more than 2.5million people have had the disease but not had their diagnosis confirmed.

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