[ad_1]
Between February 1 and March 23, 117,670 Danes were screened with PCR and antigen testing in 48 hours. 4,069 of the pcr tests gave a positive answer, meaning that the person was infected with the sars-cov-2 virus, while the number of the antigen tests was only 2,159. This means that 1,910 people (47 percent) received a false negative response from antigen tests.
“You can think of antigen testing as a very wide sieve. It catches the most contagious, but not everyone who can potentially become infected. Therefore, we consider the antigen test as a screening tool. It is an additional tool for finding and fighting viruses, “says Tyra Grove Krause of the Swedish Serum Institute in a press release.
Danish authorities emphasize that a negative response to antigen tests does not mean that one can violate coronary restrictions.
To do the thing even more complicated, there are also many who get a positive response to rapid tests, even if they are not infected according to the pcr tests.
“Therefore, it is very important that everyone who has a positive antigen test result undergoes a PCR test as soon as possible to make sure they are infected. It is only after the subsequent negative pcr test that he is infected. we consider a confirmed case. That is, you are infected, “says Tyra Grove Krause.
Flemming Platz, press manager for the Swedish Serum Institute, tells DN that several different antigen tests are included in the study, but cannot answer how many.
– Our experience is that it is basically the same type of problem with different antigen tests. We only consider antigen tests as detection, which must be confirmed by PCR tests, he says.
According to the Swedish Public Health Agency There is a wide range of antigen tests from several different vendors. Performance varies, while several of the tests have largely not been evaluated by an independent actor.
The reliability of antigen tests depends, among other things, on when they are used in the course of infection. The probability that the test can detect antigens increases with higher virus levels in the sample, ”writes the Swedish Public Health Agency in a guide for the use of antigen tests in covid-19.
The tests are designed to directly detect the protein produced by the virus as it multiplies in infected cells.
“Antigen tests are generally less sensitive than PCR, as direct detection means that higher levels of virus are needed in the sample for antigen tests to be positive. This means that a negative test result does not exclude covid-19, “the report states.
DN has contacted the Medical Products Agency and the Swedish Public Health Agency for more information.
Read more:
Seven people die from blood clots in Britain
Tegnell and Bergström: this will be the summer of 2021
