The rapid spread of SARS-CoV-2 coronavirus infection has led to the development of molecular and serologic tests in a short period of time. While tests such as RT-PCR have applications in the immediate diagnosis revealing the presence of the virus, serological tests can be used to determine previous exposure to the virus and complement acute diagnosis. Antibody production can occur as early as 5 days post-infection. Both IgM and IgG specific anti-SARS-COV-2 antibodies can be a useful tool to test faster and larger groups of individuals. The objective of this study was to carry out a review of the different serological tests offered to detect antigen or antibodies against SARS-CoV-2. This information should be useful for decision takers in different countries to choose a test according to their needs. Based on web pages that listed serological assays, we found 226 coming from 20 countries, the majority are indirect tests for specific antibodies detection (n 180) and use immunochromatography methods (n 110) with samples coming from blood-derived products (n 105). Measuring IgM/IgG at the same time (n 112) and a procedure time of <20 min (n 83) are the most common. The overall average sensitivity was 91.8% and specificity was 97%. Most of the tests are currently for in vitro diagnosis (IVD).This information gathered could change day by day due to the expedite process of production and emergency of authorization use.

Objective: To determine whether prepandemic sera from patients with Chagas disease recognise SARS-CoV-2 antigens. Materials and Methods: Forty sera from patients with Chagas disease were tested for the presence of IgG cross-reactivity against the nucleocapsid protein (NP) and spike (S) SARS-CoV-2 proteins by ELISA. Positive samples were tested again using a different ELISA and CLIA, both against NP. Results: None of the sera from patients with Chagas disease, previously confirmed as positive for the presence of anti-Trypanosoma cruzi antibodies reacted against the SARS-CoV-2 S protein, and six samples tested positive for the NP antigen (15%). The six positive samples were re-tested, five remained positive by ELISA and all were negative by CLIA. Conclusion: According to our data, false-positive results might be a concern in the detection of SARS-CoV-2 antibodies in patients with Chagas disease.

Background: COVID-19 produced by SARS-CoV-2 infection has spread worldwide. There is a growing need for immunological assays to detect viral specific antibodies or viral antigen. Current standard of diagnosis is reverse-transcriptase polymerase chain reaction (RT-PCR) in nasopharyngeal swabs. However, serological tests can be used to determine previous exposure to the virus and complement the diagnosis. IgM and IgG SARS-CoV-2 specific antibodies can be detected as early as one week after infection and assays can be useful to test large groups of individuals. This work revised the available information concerning assays that detect antibodies and antigens for SARS-CoV-2. Methods: Three sources of information were used: technical data sheets (TDS), web pages of the company's products, and published articles in Pubmed with reference to the use of diagnostic kits. All the information was revised until April 5 th 2020. Results: There were 226 tests coming from 20 countries, mainly from China. TDS were found only in 50 (22.1%). Most assays detect specific antibodies (n 180) based on immunochromatography methods (n 110) and use blood-derived samples (n 105). Assays for antibodies detection measured mainly IgM/IgG (n 112) and the most common procedure time was <20 min (n 83). Internal control referred as sensitivity and specificity was found only in 18.6% (n 42) of the assays. The majority of the tests are currently for in vitro diagnosis (IVD). A total 165 articles were found on PubMed, 15 were included and only 4 used the commercial kits reviewed. Conclusions: Due to the urgency of producing diagnostic tests for SARS-CoV-2, there is a broad offer of kits. Many tests need additional information for their application. The data collected may be useful in the selection of assays, but more and higher quality information is needed.