Q# 05, HOW RELIABLE ARE THE COVID-19 RAPID TESTS?
The PCR test is extremely accurate when carried out carefully by experienced technicians in a well-equipped lab. Because it specifically detects genes found only in the Sars-CoV-2 virus, it will produce very few false positives, said Andrew Preston, reader in microbial pathogenesis at the University of Bath. False negatives — which indicate wrongly that someone is clear of infection — are more of a problem. They often result from problems with collecting and processing patient samples. For other viruses, false negative rates of 10 per cent are widely accepted and they can reach as high as 30 per cent. Therefore PCR tests “have more often been used to confirm an infection rather than give someone the all clear”, said Dr Gill at Warwick Medical School.
The accuracy and reliability of the new antibody tests will not be known until they have been validated and technicians have gained more operating experience. Spain’s ministry of health last week withdrew 8,000 Chinese-made testing kits delivered to Madrid’s regional government because of worries about inaccurate results. But the manufacturer Shenzhen Bioeasy said the problems may have been because of incorrect sample collection or use of the product.
“It is not easy to quickly and massively ramp up testing capacity when it requires both high-quality kits and properly trained staff.”
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Edited by caliban, 21 May 2020 - 12:43 PM.
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