Abstract. This study investigated the effectiveness of serological tests for COVID-19 detection. Specifically, it analyzed the results of two different serological tests and a nasopharyngeal swab test for a sample of 879 people. The area under the ROC curve was measured for both serological tests to determine their overall diagnostic accuracy, while the sensitivity and specificity of the tests were analyzed at different thresholds to identify the optimal cutoff points. The findings suggest that serological tests have the potential to be a valuable tool in early detection of COVID-19, which can help reduce the spread of the infection. These tests can also provide additional information on the presence of antibodies, which can help identify individuals who have already been infected with the virus and may have developed some level of immunity. This research contributes to the growing body of knowledge on COVID-19 testing and detection, and it has important implications for public health and clinical practice. By identifying the most effective ways to use serological tests, healthcare providers can improve their ability to detect and respond to COVID-19 cases, ultimately helping to mitigate the impact of the pandemic.