A standard PCR molecular test for coronavirus is more likely to be false negative in those people who are tested either early or late in the course of the infection..
For’ this is people with Covid-19 symptoms who get tested and tested negative - especially those living in areas with high incidence and high viral load- it would be good to do it again in a few days, to confirm the result. As reported by ΑΠΕ-ΜΠΕ, this emerges from a new scientific study in the US, Led by Dr. Caitlin Dagdale of Harvard University School of Medicine and Massachusetts General Hospital, published in the infectious disease journal "Open Forum Infectious Diseases", according to "Nature".
The research was done in 15.011 adults who had done a molecular test , of which the 2.700 got a negative result and did a second test within a few days. From those who did the repetitive molecular test, the 60 (rate 2,2%) were finally positive for the SARS-CoV-2 virus.
From them, six out of ten (rate 60%) they had done the first negative molecular test - which eventually turned out to be false negative- or one day before the onset of their symptoms (the 18 in 60 or percentage 30%), or after the seventh day from the first symptoms (also percentage 30%).
From this, The researchers concluded that the molecular test was more likely to be false negative or in the early pre-symptomatic stage of Covid-19 infection., or at an advanced stage after the first week with symptoms. According to the study, the vast majority of people with a false negative test (the 52 in 60 or percentage 87%) had coronavirus symptoms, while several also had a chest x-ray with an image reminiscent of Covid-19.
Molecular PCR tests (molecular polymerase reaction) -the most reliable in the midst of a pandemic- detect the genetic material of the coronavirus in the sample taken from the nose or throat, while rapid antigen tests (rapid) detect specific proteins (antigens) on the surface of the coronavirus.