Coronavirus antibody testing criticised by leading academics

25 June 2020, 08:59

A home testing kit for Coronavirus (COVID-19) pictured at an address in London
A home testing kit for Coronavirus (COVID-19) pictured at an address in London. Picture: PA

By Matt Drake

Concerns have been raised by leading academics over the performance of coronavirus antibody tests, the clinical reasoning for them and the cost.

The tests were designed to test whether a person has had Covid-19 in the past and the first phase of the Government's antibody testing programme is set to assess NHS and care staff.

Clinicians will also be able to request the tests for patients in both hospital and social care settings if they think it is appropriate.

But a letter from academics and clinicians, published in The BMJ, raises concerns about the performance of the tests, the clinical reasoning for them and the cost.

"We are writing to express concerns over aspects of the establishment of SARS-CoV-2 antibody testing in England," the team of experts wrote.

"NHS England and NHS Improvement wrote to NHS trusts and pathology networks on 25 May 2020, asking them to offer antibody testing at short notice and ramp up capacity to thousands of samples a day.

"We have three concerns about the request. Firstly, there is no specific clinical indication for the test on an individual basis. Secondly, the performance of these assays has not yet been assessed to the standard typically required of a novel test. And thirdly, the resource implications are not considered."

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They said that a positive or negative test result would not alter the management of a patient and added that a positive result "does not indicate immunity".

"The concept of 'immune passports,' allowing healthcare workers or others to work, has not been established. Those with a positive antibody test should still consider themselves at risk and follow infection control policies designed to prevent nosocomial spread and risk of infection. There is, therefore, no benefit to healthcare organisations or to others in knowing the status of employees at present."

They also raised concerns about the "unproved performance" of the tests, adding: "The assay is being rolled out at an unprecedented pace and scale without adequate assessment, potentially compromising public trust in pathology services in the future."

The letter adds: "NHS England requires the result to be available in 24 hours. Given that routine testing of patients is neither clinically urgent nor meets a clear public health need, this push to introduce a non-evidence based test for uncertain gains risks inefficient use of scarce resources."

The Government website states: "While the results of an antibody test will not allow people to make any changes to their behaviour, such as easing social distancing measures, there's clear value in knowing whether NHS and care workers and hospital patients and care home residents have had the virus, and in collecting data on the test results."

A spokesman for Roche Diagnostics UK told The BMJ: "We are rolling out antibody tests to the NHS as part of the crucial next step in understanding the spread of this virus, and providing greater confidence and reassurance as we move into the next phase of our response to this pandemic."

A Public Health England spokesman said: "Our evaluations have been completed in record time using the samples and tests that were available to us. We are confident that the volume of samples and methodology was of a high standard."

In a statement to The BMJ, the Department of Health and Social Care said: "We do not currently know how long an antibody response to the virus lasts, nor whether having antibodies means a person cannot transmit it to others."

But the spokesman reiterated that antibody testing "will play an increasingly important role as we move into the next phase of our response to this pandemic".