The sensitivity of the main test carried out to detect the corona virus is under questions by scientists, as they show positive results even for dead corona virus fragments.
Most people could infect others for about a period of a week whereas can test positive even after several weeks have passed. This has forced researchers to conclude that this could be the reason leading to the over-estimation of current scale of growth of the pandemic.
Prof Carl Heneghan reportedly said, “Instead of giving a (Yes/No) result based on whether any virus is detected or not, tests should rather have a cut-off point so that a very small amount of virus does not trigger any positive case.”
He believes the detection of traces of old virus could partly be the reason why the number of cases is rising while hospital admissions remain stable.
As reports say, the University of Oxford’s Centre for Evidence-Based Medicine reviewed the evidence from 25 studies where virus specimens from positive tests were put into a petri dish to see whether they would grow.
This method of ‘viral culturing’ can indicate whether the positive test has picked up active virus which can be infectious by reproducing and spreading, or just dead virus fragments which wouldn’t grow in the laboratory, or in any human body.
Public Health England community agreed viral cultures were a useful way of assessing the results of coronavirus tests and said it had recently undertaken analysis along these lines.
It said it was working with labs to reduce the risk of false positives, including looking at where the “cycle threshold”, or cut-off point, should be set.
(With inputs from BBC News)
Ms Kalinga