Clinical performance of a chemiluminescence SARS-CoV-2 antibody assay in a cohort of healthcare workers, blood donors and COVID-19 patients

Abstract

Introduction: Serological detection of antibodies against SARS-CoV-2 has become an essential tool to test vaccine efficacy and epidemiological surveillance of COVID-19. There have been limited published studies documenting the performance of SARS-CoV-2 antibody assays within hispanic populations. Materials and methods: We evaluated the diagnostic performance of a chemiluminescence enzyme immunoassay (CLIA) on a set of 1,035 samples including pre-pandemic samples, healthcare workers (HCW), blood donors (BD) and COVID-19 positive confirmed by RT-PCR collected from April to December 2020. Results: Through a ROC curve the CLIA test had a high diagnostic performance, with an AUC of 0.9854 (CI95% 95.68-100), P<0.0001. The analysis yielded a cut-off point 0.1950, sensitivity of 98.4% (CI95% 95 91.54-99.9), and specificity of 93.8% (CI95% 79.8 - 98.9). The diagnostic performance was also evaluated comparing the results with those obtained using other diagnostic techniques. Substantial agreement with the lateral flow chromatography and RT-PCR tests was found, and a high level of agreement with ELISA, with %PPA of 91.3 (CI95% 84.0-95.5), %NPA of 97.7 (CI95% 96.3-98.6), %OPA of 97.7 (CI95% 96.3-98.6) and Cohens kappa value of 90.4 (CI95% 85.8-94.9). A logistic regression was used to determine which of the independent variables predicted reactivity to CLIA test. A higher age was associated with an odds ratio (OR) of 1.043 (CI95% 1.022-1.065), while the presence of at least one chronic disease was associated with an OR of 5.649 (CI95% 3.089-10.329) greater likelihood of reactivity. Conclusions: CLIA test exhibited excellent performance making it a suitable test for seroprevalence surveillance at the community level.