Coronavirus Infection: Informativeness and Timeliness of the Laboratory Diagnostic Algorithm in Athletes

The purpose of the study was to form a step-by-step algorithm for diagnosing the disease caused by the SARS-CoV-2 virus, taking into account the specifics of athletes’ training. Materials and methods. Such methods as analysis and generalization of data from modern scientific and scientific-methodological literature, including the results of PubMed and MedLine databases were used in the study. Results and discussion. For people who are regularly engaged in physical activity, the disease of COVID-19 has become one of the factors of heart damage in the post-covid period, which often serves as a reason for removing athletes from the training and competition process. Due to their high mobility, contact with a large number of sportsmen during training meetings and competitions, athletes are definitely in the risk group for the disease of COVID-19. Methodologically, laboratory approaches for determining the presence of COVID-19 are divided into general and specific. The latter include an express test for the coronavirus antigen, which in 15 minutes makes it possible to determine the presence of the nucleocapsid protein of the SARS-CoV-2 virus in the human body. This is important for testing athletes before training sessions and competitions, when there is an increased risk of infection, as well as for fulfilling the conditions for athletes to travel abroad. Express tests also include tests using immunochromatographic analysis to establish two classes of antibodies − M and G, detection of RNA 2019 nCoV by the polymerase chain reaction method, tests that are based on enzyme immunoassay. To determine the content of immunoglobulins, it is important to adhere to the timing of the analysis. Diagnostics by the polymerase chain reaction method allows you to directly determine the presence of the virus in the conditions of a specialized laboratory, but not earlier than the third day after infection. Immunoenzymatic (immunofluorescent) diagnostics using ELISA-kits makes it possible to detect in the blood antibodies to the coronavirus, produced by the body in the acute stage of the disease (IgM antibody analysis), i.e. 5–7 days after contact with the virus ("early phase" antibodies infections). Content limits serve as criteria for the informativeness of the test on IgM concentration: <0.9 U∙ml-1 − negative; 0.9−1.0 U ml-1 − indefinite; >1.1 U∙ml-1 − positive. A quantitative test for IgG (immunoglobulin G) antibodies to the spike S-protein of the coronavirus allows to assess the level of neutralizing antibodies to the SARS-CoV-2 coronavirus as a result of the transferred coronavirus disease COVID-19 and / or after vaccination against COVID-19. This analysis should be carried out from the 14th day after the onset of the disease or the administration of the first dose of the vaccine. Conclusion. Thus, by timely and comprehensively applying evidence-based technologies for testing and monitoring the course of the COVID-19 disease, supplementing this algorithm with careful monitoring of the functional state of the cardiovascular system, it is possible to prevent the occurrence of serious complications that can lead to the exclusion of athletes from the training process