WASHINGTON -- The FDA gave emergency use authorization (EUA) late Friday to the first SARS-CoV-2 antigen test, which provides results indicating active infection in 15 minutes.
It's less sensitive than the current PCR-based molecular tests, however, and comes with important limits on its use.
Quidel's Sofia 2 SARS Antigen FIA is a lateral flow immunofluorescent assay that directly detects SARS-CoV-2 viral proteins. It's to be used with nasopharyngeal swabs collected the same way as for PCR tests.
The EUA allows it to be performed at point-of-care (in locations with a so-called CLIA waiver) as well as in clinical labs. Nevertheless, it does require trained personnel, and can run only on Quidel's benchtop Sofia 2 analyzer.
And because Quidel's evaluation indicated it has sensitivity of only 80% relative to PCR tests, "negative results do not rule out infection," the FDA cautioned in announcing the EUA.
"With this in mind, negative results from an antigen test may need to be confirmed with a PCR test prior to making treatment decisions or to prevent the possible spread of the virus due to a false negative," the agency said.
Quidel's main validation was performed on 143 frozen nasopharyngeal swabs with known positive/negative status, according to the product's label. Of these, 59 were "true positives" according to an unspecified PCR analysis. The test was perfect in identifying the 84 negative samples, but also gave negative results to 20% of the true positives.
Under the distribution of positives and negatives in these samples -- with about one-third positive -- the Quidel assay had a negative predictive value of 88%. Because specificity was 100%, so was the positive predictive value.
Similar results were obtained in a second evaluation in which Quidel's own PCR test was used as the reference.
The company also said it applied the antigen test to samples containing a range of other respiratory pathogens, to identify potential cross-reactivity. These included coronaviruses causing MERS and the common cold as well as rhinovirus, various influenza and parainfluenza strains, respiratory syncytial virus, and about a dozen other viruses, bacteria, and fungi. All gave negative results on the SARS-CoV-2 antigen test.
"This is just the first antigen test to be authorized and we expect more to follow," the FDA said. "We also anticipate providing an EUA template for antigen tests, similar to ones we've released for other test types, to help manufacturers streamline submissions and help expedite our review and issuance of additional EUAs."
"type" - Google News
May 09, 2020 at 10:45PM
https://ift.tt/2WKxmGv
New Type of COVID-19 Test OK'd - MedPage Today
"type" - Google News
https://ift.tt/2WhN8Zg
https://ift.tt/2YrjQdq
Bagikan Berita Ini
0 Response to "New Type of COVID-19 Test OK'd - MedPage Today"
Post a Comment