The 5 discrepant results were for patients who presented with mild upper respiratory symptoms and single positive RT-PCR. evaluated in this study have different sensitivities for detecting antibodies in SARS-CoV-2 contamination. Sensitivity for detecting antibodies for all those three assays was higher for specimens collected 10 days after first positive PCR compared with specimens collected 10 days. Time of seroconversion is BIX-01338 hydrate usually variable and assay-dependent. BIX-01338 hydrate strong class=”kwd-title” Keywords: COVID-19, SARS-CoV-2, Serology, Seroconversion Introduction Coronavirus disease 2019 (COVID-19) is usually caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The COVID-19 pandemic which was initially reported in Wuhan, China in December 2019 has been since spreading worldwide [1]. At the time of writing this paper, The World Health Organization (WHO) has reported 21,294,845 cases and 761,779 deaths worldwide [2]. Currently, there are three types of laboratory assessments available for the detection of SARS-CoV-2. Molecular assessments detect the BIX-01338 hydrate RNA of the virus while the antigen assessments directly detect viral antigens [[3], [4], [5]]. Reverse transcriptase polymerase chain reaction (RT-PCR) is the gold standard test recommended for use by the WHO for the diagnosis of COVID-19 cases [6]. Serology assessments, on the other hand, reflect the immune response to the virus by detecting the presence of antibodies in blood. Serology assessments have generated substantial interest as a potential alternative to RT-PCR in the diagnosis of SARS-CoV-2 contamination as they have faster turn-around time and they are cheaper and easier to perform in the laboratory in comparison to RT-PCR. According to the most recent publication from the Infectious Disease Society of North America (IDSA), serology assays can be used in selected diagnostic scenarios including providing evidence of COVID-19 infection in symptomatic patients with a high clinical suspicion and repeatedly negative PCR testing, confirmation of past infection and providing evidence of infection in paediatric patients with multisystem inflammatory syndrome [7]. Current evidence indicates that SARS-CoV-2 antibodies begin to develop approximately 6C10 days after infection with SARS-CoV-2 [8,9]. IgM appears to peak approximately Efnb2 12C15 days after SARS-CoV-2 infection and persists in sufficient quantities for as long as 35 days, after which the quantity declines rapidly. IgG has been observed to peak approximately 17 days after SARS-CoV-2 infection and persist for at least 49 days [9,10]. Because of the pandemic situation and the increasing need for diagnostic testing, the Centres for Disease Control and Prevention (CDC), Food and Drug Administration (FDA) and other international organizations have supported the COVID-19 response, including development of diagnostic assays and through issuing FDA emergency use authorization (EUA) for some of these assays. Due to the high number of different serologic assays available in the market that are based on different technologies and antigenic targets, there is a considerable uncertainty regarding the accuracy and the clinical performance of these tests. We compared three of the commercially available immunoassay kits to assess their diagnostic accuracy for SARS-CoV-2 infection. We also included a fourth quantitative assay to measure antibody levels for the selection of convalescent plasma donors. Our objectives were to verify their reported performance and to compare sensitivities and specificities of different test methods. To our knowledge, this is the first study in the United Arab Emirates (UAE) that compares the performance of three different COVID-19 immunoassays. Material and methods Patients specimens Leftover blood specimens that were collected from patients admitted to Cleveland Clinic Abu Dhabi (CCAD) hospital with clinical manifestations suspicious for COVID-19 infection were utilized in this study. CCAD is a 364-bed tertiary care hospital in the United BIX-01338 hydrate Arab Emirates (UAE). Clinical Information was obtained through reviewing the electronic medical records of patients. Testing was performed at the National Reference Laboratory (NRL). Patients specimens were divided into three cohorts: the first cohort had 93 specimens to assess sensitivity, specificity and precision; the second cohort had multiple specimens collected from seven patients to evaluate seroconversion and the third cohort had 13 specimens to assess antibody levels from convalescent plasma donors. Evaluation of sensitivity, specificity and precision For the evaluation of sensitivity and specificity of the serology assays, we tested leftover blood specimens from 93 patients (63 patients positive for COVID-19 by RT-PCR and 30 negative) using the Roche and Abbott assays and from 60 patients BIX-01338 hydrate (30 positive for COVID-19 by RT-PCR and 30 negative) using the Euroimmun assay (first cohort of patients). The 30 COVID-19 negative patients included 10 who had a negative COVID-19 RT-PCR and 20 patients whose samples were previously collected before the COVID-19 pandemic..