Coronavirus antibody test impresses some UK scientists

  • Peter Russell, Medscape.com

  • UK Medical News
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Health officials in England have approved an antibody test to help determine if a person has been exposed to the SARS-CoV-2 virus and whether they have developed antibodies against the virus.

It was previously said that tests put through their paces were not reliable enough.

The latest results have been described as a "very positive development" while other experts wanted more details.

The Elecsys Anti-SARS-CoV-2 serology test has been developed by the Swiss pharmaceutical giant Roche, which has claimed specificity greater than 99.8%, and sensitivity of 100%.

Scientists at a Public Health England (PHE) facility confirmed the positive assessment during trials last week.

Negotiations Between the Manufacturer and the DHSC

Prof John Newton, national coordinator of the UK Coronavirus Testing Programme, said: "We were confident that good quality antibody tests would become available when they were needed.

"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%.

"This is a very positive development because such a highly specific anti-body test is a very reliable marker of past infection. This in turn may indicate some immunity to future infection although the extent to which the presence of antibodies indicates immunity remains unclear."

Roche is reported to be in talks with the Department of Health and Social Care about possible use by the NHS in England.

It is unclear at this stage whether health officials in Scotland, Wales, and Northern Ireland will follow suit if the test is adopted in England.

The test has already been approved by medical regulators in the EU and the United States.

According to Roche, the test is an immunoassay for the in-vitro qualitative detection of antibodies (including IgG) to SARS-CoV-2 in human serum and plasma.

After a blood sample is taken, the test, which is based on an in-solution double-antigen sandwich format, can detect antibodies to the novel coronavirus causing COVID-19.

Hospitals and laboratories will be able to run the test on Roche's cobas e analysers.

The company says that because of its large global manufacturing capabilities it will be able to deliver millions of testing kits each month.

Game Changer?

Matt Keeling, professor of populations and disease at the University of Warwick, told the Science Media Centre: "This could be a complete game-changer.  The key is the very high sensitivity and specificity.

"High sensitivity means that if you've previously had coronavirus the test will correctly identify this; this likely means that such individuals are at lower risk of catching the virus again."

Dr Alexander Edwards, associate professor in biomedical technology at the University of Reading, commented: "At the moment we don't know if having antibody will fully protect from infection and for how long, so a specific test still doesn't answer all the questions.

"But false positives are still always a concern so it's vital to know that such laboratory antibody tests can achieve this accuracy."

Other experts had questions about the technology and the way it was tested.

Richard Tedder, visiting professor in medical virology at Imperial College London, said: "A number of manufacturers already have large platforms capable of detecting antibody and in this respect the development by Roche, is neither surprising nor remarkable. 

"Just how sensitive and just how specific it is, remains to be seen when this platform is used routinely. 

"I find it surprising that PHE appear to have given this preferential treatment and publicity over and above the existing platforms by other companies."

Prof Sheila Bird, from the University of Cambridge, wanted to see more details about the independent evaluation at Porton Down. "Meta-analysis of the results from evaluations conducted by Roche and independently at Porton Down should give consistent and precise overview of specificity and sensitivity of the antibody test, both with 95% confidence intervals," she said. 

"Results should be reported publicly in a statistically appropriate manner for this important breakthrough."

Adapted from Medscape UK.