To study the diagnostic characteristics of test systems for detecting antibodies to SARS-Cov-2 . We studied the diagnostic characteristics of two test systems for detecting antibodies to SARS-Cov-2, registered in the Russian Federation . The first test system is a kit for detecting total antibodies to SARS-Cov-2 using immunochemiluminescence analysis on the « Cobas e 411¼ analyzer (« Roche Diagnostics¼, Germany). The second test system is a kit for detecting IgM and IgG to SARS-Cov-2 (« Core Technology Co., Ltd¼, China) by immunochromatographic analysis . The biological material for the study was blood serum . We assessed: diagnostic sensitivity, diagnostic specificity, and predictive value of positive and negative results . In the test system for detecting total antibodies to SARS-CoV-2, using an IHLA, the diagnostic sensitivity and specificity were 100% ; the predictive value of positive and negative results was 100% . In the test system for the detection of IgM and IgG to Sars-CoV-2, using IHA, diagnostic sensitivity for IgM and IgG were 100% ; diagnostic specificity for IgM - 60%, for IgG - 72% ; predictive value of a positive result for IgM - 60%, IgG - 68,18% ; predictive value of negative results for IgM and IgG - 100% . The best diagnostic characteristics were found in the test system for the detection of total antibodies to SARS-Cov-2, which must be taken into account when deciding whether to purchase test systems for the detection of antibodies to SARS-Cov-2.