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New over-the-counter COVID-19 test authorized by the FDA

The test is expected to help with a shortage of at-home testing kits

by Megha Satyanarayana
October 5, 2021

A photo of the Flowflex test.
Credit: ACON Laboratories
The US Food and Drug Administration has authorized ACON Laboratories' Flowflex test, saying it will double at-home testing capacity in the US.

The US Food and Drug Administration has granted an Emergency Use Authorization to an over-the-counter (OTC) COVID-19 test that agency officials say will double at-home testing capacity. The authorization came days after the White House announced a plan of action addressing a shortage of at-home COVID-19 tests.

ACON Laboratories’ Flowflex test was authorized on Oct. 4, adding another rapid antigen test to the over-the-counter lineup. It’s one of eight authorized antigen tests, which detect the presence of the SARS-CoV-2 nucleocapsid protein.

Jeff Zients, the White House COVID-19 response coordinator, said during a briefing on Friday that large retailers like Walmart, Amazon, and Kroger have agreed to sell at-home tests at the cost they pay for them. “The at-home rapid test is under a lot of demand,” Zients said. “The manufacturing is scaling up significantly, doubling across the next couple of months, and we’re just going to keep at it to encourage those manufacturers to increase capacity and drive down the costs of that test.”

The FDA said in an announcement that ACON plans to produce more than 100 million tests per month by the end of the year. By February 2022, the company expects to produce twice that.

The inability to find at-home tests has led to people driving from store to store, monitoring online sellers, and trading tips with others. It’s also suspected, at least in part, of contributing to long lines at testing sites throughout the US.

In late May of this year, C&EN tested the four antigen and two molecular OTC teststhat the FDA had authorized at the time. These tests included Abbott’s BINAXNow, which the New York Times reported was being thrown away at a manufacturing facility in Maine at a point early in the summer when COVID-19 infections had dipped. A few weeks later, cases started spiking again, as the highly infectiousDelta variant spread.

Like BINAXNow, Flowflex is a lateral flow test. After a person swabs their nose, they submerge the swab in a liquid buffer, which is then applied to a test strip containing antibodies to the nucleocapsid protein. If the person has COVID-19, pieces of the viral nucleocapsid will bind to an antibody and travel up the strip to where a second antibody is waiting. Binding the second antibody creates a visual readout in the form of a line. ACON reports that the test gives a false negative 3% of the time and a false positive less than 1% of the time.

The Flowflex test only needs to be taken once if a person is symptomatic, according to the FDA. Other tests need to be taken twice, with days between them, in case the amount of viral protein does not meet the detection threshold of the first test.

In addition to Flowflex, three other antigen tests have been authorized since May. No other OTC molecular tests, which detect the genetic material of the virus, have been authorized since April.


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