Together with a specialist, we figure out how to get tested correctly if you feel the symptoms of COVID-19.
Pediatrician, general director of the Nearmedic network of clinics
No food or water
PCR – This is a smear that must be done in order to detect the virus in the oropharynx or nasopharynx. Therefore, if you suspect COVID-19, this analysis is prescribed. Based on its results, a decision is made on the need for urgent measures, namely, whether self-isolation and appropriate treatment are needed.
The sensitivity of PCR analysis is 80%therefore, a negative test does not yet indicate 100% the absence of coronavirus. In addition, it is known that the remains of the virus can be detected within weeks. The reaction in this case is possible positive, despite the fact that the person is no longer sick and does not excrete the virus. It also happens the other way around: with a negative result, an infection in the body is present. We must not forget about the human factor, namely about the wrong analysis.
Patients do not always know that how to behave before testing:
to get a reliable result 3 hours before taking a smear, you do not need to eat, drink, brush your teeth;
this rule also applies to chewing gum;
a few days before the study, you need to stop taking alcoholic beverages.
M and G
In addition to the PCR test, to confirm the diagnosis, they take antibody test… By the presence of antibodies of the IgM class, one can judge that a person has recently been infected with a virus. The presence of antibodies of the IgG class indicates that two to three weeks have passed since the moment of infection. However, both do not guarantee that the patient has developed protective immunity. To determine it, check for the presence of anti-RBD antibodies. Let’s try to figure out what it is.
The receptor binding domain (RBD) is a protein structure located on the corona spines of the virus. It binds its S-protein to the proteins of a human cell not with the entire surface, but only with its end, which resembles the very thorns that make the virus look like a solar corona during an eclipse. Human immunity detects the receptor-binding domains of the virus and produces anti-RBD antibodies in response, blocking them and thereby preventing the virus from entering cells.
A look ahead
Anti-RBD antibody tests are recommended to confirm the diagnosis. In addition, research results help to make decisions about the need for vaccination. If anti-RBD antibodies are already in the body, the vaccine can be delayed. These tests allow doctors to evaluate the effectiveness of vaccination, namely, to determine the strength and duration of immunity after the procedure.
There is another point: the employer, on the basis of checking the team for the presence of a virus of neutralizing antibodies, can identify those employees who are maximally protected and are able to work in an office without the danger of infection for themselves and others.
Note
The necessary antibodies may not be produced in sufficient quantities even after a previous illness. Most often this happens if the coronavirus is mild. In addition, antibodies can disappear within 6 months after illness. Over time, their number decreases in all survivors of COVID-19.