The test for SARS-CoV-2 developed by the US Centers for Disease Control and Prevention failed due to cross contamination resulting from certain lab standards not being followed, the Washington Post reports.
The US Food and Drug Administration issued an Emergency Use Authorization for the CDC's test in early February, but when the agency shipped its real-time RT-PCR-based test to public health labs around the country, most had problems with it during quality control assessments. The CDC traced this issue to a reagent in the kit that it then had to re-manufacture, setting back testing for SARS-CoV-2 in the US.
The Washington Post reports the source of these issues was the third component of the US test. The CDC test included three features: two components that detect different parts of the SARS-CoV-2 genome, an approach the Post notes is standard, as well as a third pan-coronavirus component. That component, the Post reports, appears to have had low levels of contamination, as it exhibited reactivity with known negative samples.
As the contamination was widespread, the Post says that suggests it occurred centrally where the CDC manufactured and assembled the kits. The Post reports that it confirmed an FDA finding that the CDC "violated its own laboratory standards in making the kits," which exposed them to possible contamination.