From the article: [...] [...] [...] Also: Dozens of coronavirus antibody tests on the market were never vetted by the FDA, leading to accuracy concerns - Washington Post
From the article:
Normally, to get FDA approval, diagnostic makers need to run trials to gather evidence on their tests’ performance, a process that can take months or even years. The agency is currently skipping a lot of those steps by issuing emergency use authorizations.
Manufacturers are now required to run their Covid-19 tests on a minimum of 30 positive samples and 30 negative samples. They must demonstrate to the agency that the test has at least a 95 percent sensitivity, meaning it must correctly identify at least 95 percent of the positive samples as having the coronavirus, and 100 percent specificity, meaning that it must accurately identify all the negative samples as not having the coronavirus.
But the manufacturers are demonstrating their diagnostics’ performance with what’s known as “contrived samples,” which are not taken from actual patients. A contrived sample is made by taking coronavirus RNA made in a lab and putting it into a medium that mimics nasal mucus.
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“Clinical studies, which take months to run and would be part of a regular (nonemergency) test approval process, are needed to give us an exact percentage of false negatives and false positives,” Roche spokesman Mike Weist wrote in an email. “We will continue to work with the FDA on ongoing studies post-EUA that will allow us to potentially say more in the future.”
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Even if the sample is taken correctly, mishandling of the swab can also invalidate the result. RNA is similar to DNA but due to chemical differences is a much more fragile material and degrades more readily. This coronavirus is an RNA virus, essentially a string of RNA encased in a membrane “envelope.”
Abbott, one of the test makers, said that it recommends that samples be kept for no more than eight hours at about 60 to 85 degrees Fahrenheit, or refrigerated for 72 hours. “People should make sure it is tested in a timely fashion,” Abbott said in its statement to ProPublica.
None of this bodes well for the numerous labs that have reported backlogs of tens of thousands of samples that are waiting to be tested.
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The FDA, meanwhile, is lowering the bar even further. On March 16, it issued new guidance allowing manufacturers to distribute tests even before receiving emergency use authorization, for a “reasonable period of time” — about 15 days — after a diagnostic maker had validated the test internally and while preparing its request to the agency for an EUA.
Local governments are desperate enough for tests that they’ll buy them without assurances of accuracy at all. Chicago recently ordered 11,000 antibody tests made in South Korea that had not been reviewed by the FDA but are legal to distribute as long as they include several disclaimers including a recommendation that any negative result be confirmed with a diagnostic test.
From the article:
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Also: Dozens of coronavirus antibody tests on the market were never vetted by the FDA, leading to accuracy concerns - Washington Post