How accurate antibody tests are for detecting COVID-19?

Cochrane recently published a review of studies looking at the accuracy of COVID-19 antibody tests. Here we summarise the main conclusions of the first review which provides authentic information to policy makers worldwide including those in India to make them aware of the status of the technology and the improvements needed for its proper use. A few months ago our capability was to carry out only about 100 tests per day. With the introduction of rapid tests the total number now is over 200,000 per day. With the present rate at which the virus is spreading across the country, the number of tests may also be scaled up. The experts from the University of Birmingham led Cochrane researchers from universities across the world to search through 10,965 unique references on COVID-19 available at the end of April 2020 to find studies that reported results of antibody tests in groups of people known to have (or have had) COVID-19 and others known not to have had COVID-19 infection. Sensitivity and timeliness of the test The researchers found that the sensitivity (the proportion of the people who have had COVID-19 that the test can detect) of antibody testing is very closely related to when the test is performed. When we do the test: • Between 8 to 14 days after onset of symptoms, tests of the IgG and IgM antibodies correctly identified only 70% of people who had COVID-19. • Between 15 and 35 days after symptoms first began, antibody tests accurately detected over 90% of people who have COVID-19 • Beyond 35 days after the beginning of symptoms, the researchers found that there are insufficient studies to estimate the sensitivity of antibody tests. The reviewers also found that tests only wrongly diagnosed COVID-19 in 1% to 2% of people without COVID-19. A press release from Cochrane illustrated some typical results. In a sample of 1000 people where 200 people (20%) really have COVID-19 (this is typical of workers in a hospital setting where COVID-19 patients have been treated): • 193 people would receive a positive test result but 10 (5%) of those people would not have COVID-19 (known as a false positive result) • 807 people would receive a negative test result but 17 (2%) of those people would have COVID-19 (known as false negative result) • In a population where COVID-19 was more common there would be more false negatives and fewer false positives.

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We can fully conclusive with the result of RT. -PCR now a new problem is raising lack of infrastructure in india false positive or negative are discharged from hospital after 2or 3 days treatment and monitoring and ask to complete further treatment at home.therefore no such study is carried out in india we are shown one side of coin. Informative and educative post but only academic purpose.

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Screening test should have reasonable sensitivity which the presently available Rapid Ag tests are lacking. RT PCR is the Gold standard test . Companies should come out with a more sensitive test as are available for HIV, Hepatitis etc.

Rapid antigen test is for screening of Large population. Where as RT PCR can be used for confirmation of cases with higher sensitivity.

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Antigen test pick up only 50 percent by Dr phadke SRL i will adv RT PCR clia 98 percent accuracy in web seminar

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Thnx for sharing

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Very nice information and update

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Nice information

Informative

What' done in community sero survey?

Nice update

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