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(CNN) – A new large-scale international review of rapid COVID-19 tests finds that few of them meet the World Health Organization’s minimum acceptable performance standards.
There are two types of rapid tests: molecular tests, including PCR, which are considered the gold standard of molecular diagnostics; and rapid antigen tests, which detect virus proteins. Proponents of rapid tests say these diagnostics can be used to quickly test people as businesses and society continue to reopen. Airlines are already using rapid tests to screen passengers for flights.
By looking at antigen tests, the independent Cochrane research group, a collaboration of researchers and healthcare professionals from 130 countries, found that they were best used during the first week after someone started experiencing symptoms. Under those conditions, the tests correctly identified 78% of people with COVID-19. Overall, when used to test symptomatic people, rapid antigen tests positively identified 72% of people who had COVID-19.
When antigen tests were used among asymptomatic people, the tests were much more effective in ruling out an infection than in identifying it. The tests correctly identified a negative COVID-19 result about 99% of the time in people who only had COVID-like symptoms or were not exhibiting any symptoms. However, when tested among people with a positive COVID-19 diagnosis, rapid antigen tests only correctly identified them 58% of the time.
The reviewers also found a wide discrepancy in precision between the tests, ranging from 34% to 88%. WHO minimum standards require a test to identify at least 80% of people with an infection and 97% of those without. The SD Biosensor STANDARD Q and Abbott Panbio antigen tests were identified as the two most accurate tests reviewed.
By looking at rapid PCR tests, the researchers found that, on average, they positively identified an infection 95% of the time and correctly identified a negative diagnosis 99% of the time. However, the researchers noted that these findings had limitations, because the majority of the evaluated studies relied only on the Abbot ID Now and Xpert press rapid PCR tests. There were insufficient data to assess when the tests were most accurate in relation to the onset of symptoms.
This story was first published on CNN.com, “Few rapid COVID-19 antigen tests meet WHO standards, according to a review”
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