Covid-19

At-home Covid testing subject to ‘false negative and positive results,” FDA warns

ACON main manufacturing facility in China. Photo credit ACON.

Manufacturer says positive test also may indicate presence of antibodies from past infection

by Guy Page

An at-home, over-the-counter COVID-19 test was given Emergency Use Authorization (EUA) by the Federal Drug Administration Monday – along with an FDA doctor’s warning that “all tests can experience false negative and false positive results.”

“Today’s authorization for the ACON Laboratories Flowflex COVID-19 Home Test should significantly increase the availability of rapid, at-home tests and is expected to double rapid at-home testing capacity in the U.S. over the next several weeks. By years end, the manufacturer plans to produce more than 100 million tests per month, and this number will rise to 200 million per month by February 2022,” Dr. Jeff Shuren, director of FDA’s Center for Devices and Radiological Health, said Monday.

However, Shuren offers this cautionary statement: “The FDA wants to remind patients that all tests can experience false negative and false positive results. Individuals with positive results should self-isolate and seek additional care from their health care provider. Individuals who test negative and experience COVID-like symptoms should follow up with their health care provider as negative results do not rule out a COVID-19 infection.”

Shuren does not discuss the ACON test’s statistical propensity for false testing. However, an ACON fact sheet says the test locates antibodies – which can be either a sign of past infection from which the patient is recovered, or current infection.

Yesterday, following Monday’s EUA approval of the home testing kit, the Biden administration pledged another $1 billion to purchase and distribute the in-home tests, in addition to $2 billion previously authorized.

Governor Phil Scott backs the Biden Administration’s plan to invest billions to expand rapid at-home COVID-19 tests for Americans, he said in a press statement yesterday:

“Increasing access to rapid at-home testing will be important as we continue moving forward and I applaud the President’s focus on this important tool.

“The introduction of highly effective vaccines, boosters and early treatment options has significantly lowered the risk for everyone, but especially the older, medically vulnerable population most at-risk. As a result, we are able to return to more normal activities and begin to address the consequences of the most aggressive COVID-19 mitigation measures. These consequences like increasing hospitalization for significant non-covid illnesses, increasing mental healthcare needs, rising substance use, overdoses and domestic violence, and the economic insecurity of many families and employers. The science tells us that as we move forward, COVID-19 will continue to circulate like other viruses. As America navigates that transition from pandemic to endemic, expanding access to rapid testing will change the game, giving us another, far faster and more convenient tool we can use at home to help the country moving forward.

“Vermont and our neighbors in New England have proven the power of vaccines and the importance of robust testing. I look forward to learning more about the federal initiatives and working together with the President and his team to lead the way forward.”

The kits will likely be manufactured in China. The ACON website says, “Our state of the art manufacturing facility located in Hangzhou, China is ISO13485: 2016 certified, FDA registered, and has been inspected by US FDA.”

An ACON fact sheet says the new at-home kit tests for the presence of COVID antibodies, and:

“A positive test result with the SARS-CoV-2 antibody test indicates that antibodies to SARS-CoV-2 were detected, and the individual has potentially been exposed to COVID-19.”

“If antibodies are present, it often indicates a past infection but does not exclude recently infected patients who are still contagious.”

“False positive results may occur due to cross-reactivity from pre-existing antibodies or other possible causes.”

“Due to the risk of false positive results, confirmation of positive results should be considered – using a second, different antibody assay that detects the same type of antibodies.”

“A negative test result with this test means that SARS-CoV-2 specific antibodies were not present in the specimen above the limit of detection. However, patients tested early after infection may not have detectable antibodies despite active infection.”

“In addition, it is not certain that all infected patients will develop a detectable antibody response to SARS-CoV-2 infection. A negative result should not be used to rule out infection.”

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Categories: Covid-19

7 replies »

  1. Apparently, Scott has stumbled upon something unavailable to mere Vermont peasants and taxpayers- “The introduction of highly effective vaccines, boosters and early treatment options has significantly lowered the risk for everyone,”

    Tell me Phil, Where are these things you speak of? Where might I get them? The current vaccine and booster isn’t- and early treatment options have been banned by the federal government.

  2. Some of the currently authorized and available kits such as the one from Abbot Lab have been found to have an accuracy rate of only 44%; a coin flip should do better!

    And these new ones are manufactured in China? Seriously, they gave us Covid and now they get to profit from it once again?

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