Serological tests are designed to determine the current or past presence of an infection by a microorganism. This is done by measuring the level of protein in the liquid portion of the blood. These proteins are usually antibodies.
Serological tests have been used for several decades in medicine for the diagnosis and monitoring of microbial and viral infections. The results of antibody tests can be recognized on a laboratory report by the words “IgM”, “IgG” or “total antibodies” in the name of the test. Several serological tests can be performed on a single drop of blood in less than 15 minutes, sometimes using devices that can be carried to the patient's bedside. This technique is also known as Point of care testing (POCT).
Serological tests are very useful during a pandemic such as that of COVID-19 to inexpensively assess the percentage of the population that has been affected by the virus, a good proportion of whom are symptom-free. The presence of high levels of IgG antibodies could demonstrate protection against reinfection with CoV-2-CoV-SARS (COVID-19) and, when a vaccine becomes available, identify priority populations for immunization.