Serological tests play an important role in the surveillance and management of epidemics or pandemics, as well as in acquired immunity studies. Currently, COVID-19 serology is performed by well-established immunoassay techniques, which provide high sensitivities, but require specialized laboratories with trained personnel and processing times of 3 to 48 hours. A much faster and easier method is the lateral flow assay—such as the rapid diagnostic tests sold in pharmacies. However, the latter are not fully reliable, as they exhibit only moderate sensitivity and specificity.