Serological tests can be used by scientists to measure the antibody response of an individual who can help you determine if someone is infected with the virus COVID-19 in the past. These tests might be of interest to an individual if they had not carried out a PCR test when he suffered from symptoms in the past or to determine if someone has had an infection asymptotic.
Although many clinics and private laboratories provide serological tests, these are not generally used by the travel or the target locations concerned about the current health of someone and if you have been infected by the virus.