In the statement, Swedish health authorities said that the PCR (polymerase chain reaction) testing kits, manufactured by Shenzhen-based genome sequencing company BGI Genomics, were unable to distinguish between very low and no viral genetic material.
Karin Tegmark Wisell, head of the agency’s microbiology department, said: “The supplier must adjust the performance that is required for this test to be used.” She said the findings illustrated again the importance of having quality control tests to detect such errors.
The incorrect results affected nine regions in the country in a 5-month span between March and mid-August, during which people who had mild or no symptoms at all received false positive outcomes. The agency indicated that the same kind of testing kits have been shipped to many countries other than Sweden and that it has informed corresponding authorities in Europe and the World Health Organization.
