Diagnostic Performance of Serological Assays in the Detection of SARS-CoV-2: A Review

Introduction: The gold-standard method for diagnosis of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or COVID-19) foresees the examination of respiratory tract swabs by real-time reverse-transcription polymerase chain reaction (rRT-PCR). Another group of diagnostic tests, developed to overcome the limitations of RT-PCR, includes the serological assays, which have the purpose of detecting the antibody response to SARS-CoV-2 infection (IgM and IgG titers). The aim of this review was to establish the diagnostic capability of the existing serological tests in the detection of SARS-CoV-2 infection. Materials and Methods: Electronic research was conducted in PubMed, Scopus, Science Direct and Cochrane Library, and only 10 articles, testing 10 different types of serological assays, met the inclusion criteria and were consequently submitted to quality assessment and data extraction. Quantitative data about the sensitivity, specificity, positive/negative predictive value and IgM/IgG titer provided by each antibody test were reported in our review. Results: Almost all the serological tests used in the included items were recorded to ensure high sensitivity and specificity, identifying the presence of IgM and IgG antibodies against SARS-CoV-2 in patients with certain COVID-19 diagnosis (confirmed by RT-PCR) and in participants with suspected infection (SARS-CoV-2 clinical diagnosis and/or RT-PCR negative subjects). Conclusions: Serological tests may represent reliable diagnostic tools in the detection of SARS-CoV-2 infection, and they could be implemented complementary to real-time RT-PCR.