To help understand and combat the novel coronavirus pandemic, testing to identify who is infected with the virus or has previously had contact with it is crucial. To identify whether a person is currently infected—and thus potentially infecting others—diagnosis is made using RT-PCR, the method we explained previously.
However, once the infection subsides, RT-PCR can no longer identify the virus, and at this point, serological testing becomes important. This type of test should be performed at least 10 days after the onset of symptoms, as it captures the antibodies the body produces to defend itself against the virus. Additionally, this test can also detect those who have had contact with the virus, developed antibodies, but have not shown symptoms—a case known as asymptomatic.
Serological tests, therefore, use patients' blood to assess the presence of antibodies. These tests contain antigens that are specific to the antibodies produced against Covid-19. If the person has been in contact with the virus and produced antibodies, these will bind to the antigens present in the tests and produce a positive result.
Regarding this type of technique, it is possible to state that serological tests require good standardization before they are available to the public to avoid generating false positive or false negative results. These tests are less expensive and can be ready within a few hours, which are advantages compared to RT-PCR testing.
Therefore, both RT-PCR and serological tests are essential at this time. It is important to emphasize that they must be administered at the correct time of infection so that their results can be converted into the best actions and treatments. Another important point is that it is not yet fully understood whether the presence of antibodies to Covid-19 guarantees that a person will not be infected a second time and develop symptoms. However, several studies are being carried out so that we can learn more about the disease and be successful in combating it.
