They are performed through a nasal or saliva sample and detect the virus protein very quickly: in a matter of 10 – 15 minutes. The problem is that «to date we did not have tests with the necessary sensitivity and specificity.» If achieved, they would be perfect for making a first screening of the population because it would help to unblock the overflow of the laboratories.
They are made through blood tests and allow detecting the antibodies produced after contact with the virus. If the result in this last test is positive, it means that there are immunoglobulins; the person tested has already been exposed to the virus, and it remains to be known whether it is an active or past infection. The answer to that question comes by studying the types of immunoglobulins, which can be IgM or IgG. If the IgM is negative, there is no current infection with the virus, and if it is positive, there is an acute infection. Regarding IgG, if this marker is negative, it means that the person has not been in contact with the virus in the vast majority of cases, although it may be the case that contact with the virus is so recent that it is not yet known. have generated antibodies. If the IgG is positive, it indicates that there was an infection in the past, and not acute, because it is understood that there were no symptoms if the patient did not find out.