Timing is key when it comes to getting accurate results from Covid-19 antibody tests that are used to determine if someone has been infected with the novel coronavirus, according to a new Cochrane Review paper.
Antibody tests are better at detecting Covid-19 in people two or more weeks after their symptoms started, but there is not yet enough evidence to determine how well they work more than five weeks after, or among people who had milder disease or no symptoms at all, suggests the review, published in the Cochrane Database of Systematic Reviews on Thursday.
"Time is critical. Use the test at the wrong time – it won’t work," Jon Deeks, professor of biostatistics and head of the Biostatistics, Evidence Synthesis and Test Evaluation Research Group at the University of Birmingham in England, who was involved in the review, said during a virtual press conference with reporters on Thursday.
"This is largely driven by when the samples are taken from the patients," Deeks said. "This isn’t a new science, but it’s something which has not been well thought through in a lot of the studies we were reviewing."
A Cochrane Review is a systemic analysis of published studies on a given topic, and often physicians, nurses, patients, researchers or funders turn to Cochrane evidence to help with decision-making or better understanding a medical issue.
The new review on the accuracy of antibody tests, spanning more than 300 pages, was authored by Cochrane researchers from institutions across Europe and led by experts from the University of Birmingham.