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FDA EUA Authorized Serology Test Performance
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https://www.fda.gov/medical-devices/emergency-situations-medical-devices/eua-authorized-serology-test-performance
Serology tests detect the presence of antibodies in the blood when the body is responding to a specific infection, like COVID-19. In other words, the tests detect the body’s immune response to the infection caused by the virus rather than detecting the virus itself. In the early days of an infection when the body’s immune response is still building, antibodies may not be detected.
For this page, FDA has summarized the expected performance of the tests it has authorized based on the information FDA reviewed when deciding whether or not to grant these tests an Emergency Use Authorization and assuming a prevalence of 5% for PPV and NPV calculations.
Tests are also described by their Positive and Negative Predictive values (PPV and NPV).
These estimates of sensitivity and specificity are just that: estimates. They include 95% confidence intervals, which are the range of estimates we are about 95% sure a test’s sensitivity and specificity will fall within given how many samples were used in the performance validation.
The performance of these tests is described by their “sensitivity,” or their ability to identify those with antibodies to SARS-CoV-2 (true positive rate), and their “specificity,” or their ability to identify those without antibodies to SARS-CoV-2 (true negative rate). A test’s sensitivity can be estimated by determining whether or not it is able to detect antibodies in blood samples from patients who have been confirmed to have COVID-19 with a nucleic acid amplification test, or NAAT
FDA also is providing a calculator that will allow users to see the estimated performance of a single test or two independent tests based on their performance characteristics and the estimated prevalence of SARS-CoV-2 antibodies in the target population.
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