A review of studies has found major weaknesses in the evidence base for diagnostic accuracy of Covid-19 antibody tests.
The fastest test being used to diagnose people infected with the coronavirus appears to be the least accurate test. It has pointed out a substantial rate of false negatives, especially if the test is carried out soon after exposure to the virus. In these cases, tests may not catch viral material because there is not yet enough virus load in the person to be picked up. It is also possible that the poor testing technique can miss the virus. The Annals of Internal Medicine researchers considered that those tested with COVID-19 in the four days after infection were 67 percent likely to test negative, even if they had the virus. When the average patient displayed symptoms of the virus, the false-negative rate was 38 percent. The test performed after eight days after contracting the virus, but even then, there was a false negative rate of 20 percent.
It means one in five people who had the virus had a negative test result.
A false positive is a wrong test result because it shows the person is infected with COVID-19 when they are not. False positives, which are much less likely, can cause anxiety and require people to quarantine unnecessarily. Researchers examined that the PCR kit has a 90 percent accuracy, which means the results are true positives. The kit also shows a 10 percent inaccuracy, it means the results will be false-positives.
The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19 including symptoms, prevention and available treatment, please refer to the World Health Organisation or your national healthcare authority.