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An internal review sheds new light on what went wrong with the first COVID tests distributed by the CDC during the early days of the pandemic.
Previous investigations said contamination was the major reason tests shipped to health labs in early 2020 produced inconclusive reports and false positives.
But the CDC's internal review published in Plos ONE says a design flaw also caused problems with the testing kits.
The test kits were designed to detect the virus with primers, which bind to and copy targeted sequences, and with probes that emit a fluorescent signal when copies are made, The New York Times reported. The fluorescent signal means the virus's genetic material is present.
The probes and primers were not supposed to touch or bind to each other, but that happened sometimes in the faulty kits. And this created the false positives, The New York Times said.
By early February 2020, the CDC admitted the tests weren't working and redesigned them with the help of outside laboratories, The New York Times said.
"Since the rollout of the initial Covid-19 test, C.D.C. has implemented corrective measures and remains dedicated to the highest quality laboratory science and safety," the CDC said in a statement.
But the setback hurt the agency's reputation as the threat from COVID spread across the world.
"It's something that should have been caught in the design phase," Susan Butler-Wu, a clinical microbiologist at the Keck School of Medicine of the University of Southern California, told The New York Times. "That's one thing that you check for."
The Plos One review also said some tests were probably contaminated by synthetic fragments of the coronavirus's genetic material used at the same lab where the testing kits underwent analysis, The New York Times reported.
Sinclair Broadcasting Group: "EXCLUSIVE: Internal HHS investigation finds CDC's early test kits were 'contaminated.'"
Plos One: "Analysis of the initial lot of the CDC 2019-Novel Coronavirus (2019-nCoV) real-time RT-PCR diagnostic panel."
The New York Times: "C.D.C. Virus Tests Were Contaminated and Poorly Designed, Agency Says."
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Cite this: CDC's First COVID Tests Had Design Flaw, Report Says - Medscape - Dec 17, 2021.