How should we interpret a positive IgG result in the case of COVID-19 for the screening population?
maybe the body has developed antibodies IgG against the coronavirus.
Positive IgG indicates that; the individual has been infected, whether it was a recent or previous infection (also infectious or not), requires additional IgM testing or testing of rising IgG titre in two samples.
As long the prevalence is low there is a high number of false positive tests. A positive IgG should be checked after two weeks. If there is a relevant increase in titer, then an infection is underway and a PCR should be performed. If the titer is constant, an earlier infection can be assumed.
It depends on if you are also testing IgM (most serologic tests, also called fast tests are doing just that). Then if you are positive only with IgG than you have passed the infection a time ago. If you are positive with IgG and IgM than you have passed the infection a very short time ago. If you are positive only with IgM than it is possible you are still an active case.