Microbiology experts in Spain have said that rapid coronavirus tests that the country bought from China are not consistently detecting positive cases.
The error was discovered as Spain is in the grip of one of the worst coronavirus outbreaks in the world, second only to Italy in the number of reported deaths.
Studies on the tests done in Spain found that they had only 30% sensitivity, meaning they correctly identify people with the virus only 30% of the time, sources told the Spanish newspaper El País.
Those sources told the newspaper that the tests should have a sensitivity of more than 80%. The US Centers for Disease Control and Prevention says rapid tests for influenza are required to have 80% sensitivity.
The studies prompted the Spanish Society of Infectious Diseases and Clinical Microbiology to formally recommend not using these tests, El País reported. Health workers are now meant to use other tests that take longer to give a result.
Fernando Simón, the director of Spain's health-emergencies coordination center, said on Thursday that Spain checked 9,000 of the tests, found that their results were not consistent enough, and decided to return them.
The tests were made by a Chinese biotechnology company called Bioeasy, El País reported. Other countries, including Georgia, have bought the company's tests.
The Chinese Embassy in Spain said on Twitter on Thursday that the medical supplies China was donating to other countries did not include Bioeasy products.
It said that the Chinese Ministry of Commerce gave Spain a list of manufacturers and that Bioeasy was not among them, adding that it had not been given a license from China's National Medical Products Administration to sell its products.
Medical professionals in the Czech Republic have also said that rapid tests from China were not working properly, but it was not clear whether these tests were also made by Bioeasy.
Spain, Europe's worst-hit country after Italy, says coronavirus tests it bought from China are failing to detect positive cases
Spanish researchers found that the tests could identify cases only 30% of the time. Testing delays could hamper Spain's efforts to slow the virus.