The kits, developed by Swiss firm Roche after it joined a global race to develop an antibody test, have already been given the green light in the US.
It comes after another batch of tests, ordered by the government in mid-March, was deemed too unreliable to be used.
Antibody testing, dubbed a “game changer” by prime minister Boris Johnson in the early days of the Covid-19 outbreak, can check whether a person has previously had the new coronavirus.
The test involves taking a small sample of a patient’s blood and scanning it for antibodies, which the immune system produces in response to a virus.
It is hoped the tests could help confirm the spread of the virus throughout the nation and pave the way for people to potentially see whether they have built up an immunity to the disease.
Officials, however, have been quick to point out that the science remains unclear on whether people infected with the virus have developed an immunity, and how long any potential immunity would last.
A European Medicines Agency official has said a vaccine could be ready for approval in 2021 in an “optimistic scenario”, although it is not yet known exactly how a vaccine would work, and Boris Johnson has previously admitted one may never be found.
Which countries have antibody tests?
On Thursday it was announced the UK is in negotiations with Swiss drug maker Roche to buy millions of its antibody kits for use across Britain.
This is the first time an antibody test has been approved for use in the UK, after a separate batch of tests, ordered by the government in mid-March, was deemed too unreliable to be rolled out.
The test was praised by Public Health England after it was found to carry a 100 per cent rate of success when it came to ruling out false positives.
Roche said it found its test had a specificity (ability to exclude false positives) greater than 99.8 per cent and 100 per cent sensitivity (ability to exclude false negatives) 14 days after a person had tested positive for Covid-19 through a PCR (polymerise chain reaction) swab test, which detects whether someone has the virus or not.
Professor John Newton, the national coordinator of the UK coronavirus testing programme, said Roche’s highly specific test served as a reliable marker of previous infection.
He added: “Last week, scientific experts at PHE Porton Down carried out an independent evaluation of the new Roche Sars-CoV-2 serology assay in record time, concluding that it is a highly specific assay with specificity of 100 per cent.”
In the US alone, the Food and Drug Administration has granted 12 emergency authorisations for the sale of antibody tests.
One of these belongs to Roche, which has already started shipping its new test to labs across the world and says it plans to ramp up its production capacity “high double-digit millions” per month.
Another leading manufacturer, US-based Abbott Laboratories, has developed at least two Covid-19 antibody tests.
The firm says it has already shipped more than 7.2 million of its Architect tests to customers across the US and is also planning to deliver them to several other countries, including Italy, Spain and India.
A clinical study found the test had greater than 99.6 per cent specificity and 100 per cent sensitivity in patients tested 14 days after symptoms began.
The company, whose Alinity antibody test has also received US FDA approval, plans to ramp up production to 20 million tests in the US per month from June.
Ortho, another firm, says it plans to make several million antibody tests each month in Rochester, New York, and Pencoed, Wales, after earning approval from the FDA.
Italy’s reopening after its strict lockdown was supposed to be accompanied by a series of measures to limit infections, including a pilot project of 150,000 antibody tests, which US company Abbott Laboratories won the tender to supply.
Italy’s commissioner for the emergency, Domenico Arcuri, promised Italy would distribute antibody tests to labs on 4 May the pilot — but testing is still yet to begin.
Further delays are expected as health authorities work to contact the 150,000 people identified as potential subjects, selected for their demographic and geographic distribution. They must then get them to agree and schedule the appointment.
Commenting on Abbott winning the contract in Italy, Carlo Rosa, the chief executive of Italian biotech company DiaSorin, which is providing antibody tests to other countries, said: “The Italian government decided to go in a different direction, with Abbott ... we are going to provide tests to many countries but not to ours.”
DiaSorin is the only authorised provider of Covid-19 antibody tests in Lombardy — the northern Italian region containing Milan which is Europe’s worst-hit area— according to the Financial Times.
It is also delivering tests to Belgium, Israel and Germany.
Germany has already rolled out antibody tests across the country and is conducting studies to determine how much of its population has been infected by Covid-19.
Researchers have so far found 14 per cent of the population has previously been infected, according to The Local.
Roche, the same company expected to supply antibody tests in the UK, is delivering three million to Germany this month, and five million a month after June.
In April, German diagnostics and medical imaging firm Siemens Healthineers also announced it was developing an antibody test.
The company said the blood tests were expected to be available by late May and that it would be able to supply more than 25 million per month from June, The Daily Telegraph reported.
Australia has reportedly spent almost $19 million buying one million antibody tests, which have proven to be of limited use.
The tests were not accurate enough as they delivered such a high rate of false positives, an Australian National University study concluded.
The kits were bought from 29 pharmaceutical companies and laboratories from around the world — 25 of which were in China, one in South Korea and one in the US, according to 7 News.
Authorities in the Chinese city where the novel coronavirus emerged launched an ambitious campaign to test all of its 11 million residents, after a cluster of new cases raised fears of a second wave of infections.
Residents of two city districts, Wuchang and Hankou, said they had been told to provide personal details including any history of nucleic acid tests and whether they belonged to any of 12 “key groups”, according to four residents and copies of questionnaires seen by Reuters.
The tests would include both nucleic acid and serum antibody tests, according to a notice issued by Wuchang district.
It is not clear if Wuhan residents will have to pay for their test or if the local government will cover the cost.
Hubei provincial authorities have gradually brought down testing costs and recently capped prices of nucleic acid and IgM/IgG antibody tests at 180 yuan (£20) and 50 yuan (£5), respectively, according to the Changjiang Daily.
The UK government is chasing a refund from two Chinese companies after it paid about £16 million for coronavirus tests that a lab at Oxford University later found to be insufficiently accurate.
Canada approved the sale of Italian company DiaSorin’s antibody test on Tuesday.
Prime minister Justin Trudeau is hopeful the information provided by the tests will help provide a wider picture of how many Canadians have been infected, and inform research into how long immunity lasts, if it occurs at all.
Gibraltar reportedly hopes to become the first country to carry out antibody tests on its entire population.
The British territory, where about 33,700 people live, will receive 35,000 tests from US company Abbott to see whether people have been infected with Covid-19, The Olive Press reports.
The country is optimistic it may be able to process 500 tests a day and trace whether people have been infected with the disease as far back as Christmas.
The Japan Sumo Association has said it will conduct antibody tests on all of its about 1,000 members, including sumo wrestlers, referees and yobidashi callers.
The testing will start early next week, with all results expected to be known by the end of June. It will be the first case of such large-scale antibody testing in the Japanese sports world.
It comes after 28-year-old sumo wrestling star Shobushi, whose real name is Kiyotaka Suetake, reportedly died from multiple organ failure caused by the virus.