This archive report was first published on 23 April 2020.
As the world grapples with the COVID-19 pandemic, China's coronavirus testing methods have come under scrutiny after a trader's experience with false negative results.
He Ximing, a 52-year-old vegetable seller from Wuhan, was initially told he did not have the coronavirus despite experiencing difficulty breathing and chest congestion in early February.
However, after multiple negative nucleic acid tests, he finally tested positive for the virus' antibodies in late March, revealing that he had indeed been infected.
He Ximing's case is not unique, with similar instances in China and elsewhere raising concerns over the accuracy of coronavirus testing.
Experts warn that unreliable testing could undermine strategies for stopping the virus and opening up locked-down economies, as pressure grows on governments to ease restrictions.
According to a Reuters tally, over 2.5 million people have been infected with the coronavirus globally, with about 177,000 deaths.
Wuhan, the epicenter of the outbreak, has recorded 50,333 cases and 3,869 deaths as of April 21.
Nucleic acid testing, which detects the virus' genome, is the main way cases are detected, but experts say mistakes can happen, such as if too small a sample is taken or if the swab misses a virus-hit spot.
Andrew Preston, a lecturer in microbial pathogenesis at the University of Bath, emphasized the need to recognize the limitations of these tests and run regular tests to ensure someone is truly negative.
Testing Times ¶
There is little consensus on what proportion of nucleic acid tests yield false negatives, with a survey by Chinese doctors suggesting a false-negative rate of about 30%.
Media reports have also highlighted cases of people testing negative repeatedly before finally getting a positive result.
Wuhan authorities have started testing residents for antibodies, and China is conducting an epidemiological survey in nine regions to determine the full extent of asymptomatic infections and immunity levels.
