Do Rats Work If Asymptomatic?
WouterThe RAT test is a simple way to detect influenza virus in the bloodstream. It involves a swab of a body part, and results take 10 to 20 minutes. It is most accurate when people have high viral loads, but it can be inaccurate when a person is asymptomatic. This is because a RAT is less sensitive when the person is asymptomatic.
In this study, researchers observed that the commonly used RAT missed 29 per cent of positive cases, and 81 per cent of positive cases without any symptoms. The authors concluded that the accuracy of RAT tests was overstated. In addition, negative rapid results did not rule out the infection in most cases, and it is not possible to know if a patient is infected if there are no symptoms.
In a recent study, researchers conducted rat screening among COVID-19 symptomatic patients, but the results were not available for asymptomatic individuals. In another study, researchers conducted rat screening in an emergency department and identified two RT-PCR-positive patients and two false-positive cases. The RAT test can be a useful initial screening test in triage. It may lead to earlier diagnosis of an infected patient.
RATs are useful for detecting high viral loads. However, they only work well if the infection is recent and there are sufficient levels of virus in the blood. However, local data on RATs’ accuracy is scarce, and it is still unclear whether they are useful for detecting asymptomatic people. The UK, for instance, used this test earlier in its response to the pandemic, and it was found to be accurate in detecting up to 80 per cent of high viral loads.
