Objective: The goal of the research is to describe the principle of operation, the procedure for performing and the application of rapid antigen tests in the diagnosis of COVID-19 infection, and to compare the frequency of positive and negative tests for SARS-CoV-2 in the Clinical Institute for Microbiology and Parasitology of KBC Split in 2020. and 2021. Material and methods: In this retrospective study, available relevant literature based on previous clinical and epidemiological research and data from the Clinical Institute for Microbiology and Parasitology KBC Split on rapid antigen tests performed in the diagnosis of infections caused by the SARS-CoV-2 virus in 2020 and 2021 were reviewed. The rapid antigen tests used for detection SARS-CoV-2 viral antigens were CLINITEST (Siemens), and nasopharyngeal swabs were taken as samples. The data were processed using the Office 2007 software package. Results: Rapid antigen tests are immunochromatographic POC tests that provide very good sensitivity and specificity in disease diagnosis. They represent a reliable substitute for the PCR method with high sensitivity in detection of acute COVID-19 infection in patients with Ct<25 or the onset of symptoms within seven days, also when it is necessary to make quick decisions and implement self-isolation measures. They are useful as a method of screening symptomatic persons for faster identification of cases and interruption of virus transmission, especially in areas of high risk and asymptomatic persons. In KBC Split in 2020 and 2021, a total of 334 rapid antigen tests for SARS-CoV-2 virus antigens were performed, of which 303 tests were performed in 2021, in contrast to 2020, when only 31 tests were performed, which is an increase of as much as 9,8 times. The total share of positive tests is 16.50% (21), while the share of negative tests is 83.50%. Conclusion: In KBC Split in 2021, a significantly higher number of tests were conducted compared to the previous year, which was contributed by new knowledge about SARS-CoV-2 infection, the development of specific BAT and the implementation of protective measures to prevent the virus from entering the hospital system. Tests approved for use must be validated before being placed on the market to meet the requirements set by WHO and EDCD and then are placed on a common list of recognized BAT.