A subset of patients with Covid-19 presents with negative RT-PCR screening but suspect CT findings. Using four commercially available anti-SARS-CoV-2 IgG immuno-assays, we found this subset constituted 9.2% of all consecutively admitted outpatients with Covid-19 in our hospital. Clinical specificity for Covid-19 of some N protein-based immuno-assays was suboptimal, as positive results were observed in control patients with recent common human coronavirus, influenza B and adenovirus infections. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s15010-020-01523-3) contains supplementary material, which is available to authorized users.
Comparison of four commercial SARS-CoV-2 IgG immuno-assays in RT-PCR negative patients with suspect CT findings