CLAIM: A photo showing a COVID-19 test kit that includes swabs labeled “positive” and “negative” proves tests are manipulated to give a predetermined result.
THE FACTS: The photo does not prove the tests are being manipulated. The swabs labeled “positive control” and “negative control” are included in test kits for quality control purposes to make sure the tests work properly, a standard for most rapid diagnostic tests. As the COVID-19 variant omicron generates a renewed wave of infections around the world, social media users began recirculating a photo from several months ago to falsely claim that COVID-19 test results are being planned in advance and that tests are unreliable.
One recent Instagram post showed a photo of a COVID-19 test kit manufactured by ACON Laboratories, which included test swab packages labeled “positive control swab,” and “negative control swab.” The post added the caption “Picture taken secretly by a nurse on shift. Name not mentioned for obvious reasons.” The same photo has been circulating online since at least spring 2021. However, the positive and negative control swabs are not used on patients, they are used to make sure the test kits work.
The swabs in the photo were part of an antigen rapid test first distributed in December 2020 by ACON Laboratories that was marketed for professional use. In this version of the test, a section of the instruction manual labeled “quality control” stated: “These control swabs should be used to ensure that the test cassette and that the test procedure is performed correctly.”
William Anderson, a technical support specialist with ACON Laboratories, confirmed to The Associated Press that this is the purpose of the swabs, and said it is “common practice” to include such control samples. ACON’s positive control swab is precoated with a SARS-CoV-2 recombinant antigen, according to the test kit instructions. Recombinant antigens are manufactured artificially in a lab.
When the positive control swab is used on the kit, it is supposed to produce a positive result to demonstrate that the test is functioning accurately. Similarly, the negative swab should show a negative result. The controls are often used by sites that perform a high volume of tests, according to a spokesperson for the U.S. Food and Drug Administration.
Loren Williams, a professor of chemistry and biochemistry at Georgia Tech, said the falsely captioned photos were “misrepresenting normal features” of these diagnostic tests. “For any good assay you need both positive and negative controls,” Williams wrote in an email to the AP. He added: “You cannot believe a negative result if your positive control is not positive. And a negative control ensures that your reagents are not contaminated. If you get a positive result in your negative control, then you generally have a contamination problem.” A similar claim was made on Twitter about swabs found in tests by Abbott Laboratories. The company responded in a statement clarifying that the labeled swabs are to make sure the tests work.
— Associated Press writer Sophia Tulp in Atlanta contributed this report.