Infections are blood-borne diseases which pose the greatest burden to the health care systems worldwide. Their incidence and prevalence are measured in millions, but what concerns us the most among the infections of interest (HIV, HBV and HCV) is the HBV infection which represents the greatest threat to world’s population. However, due to its specific epidemiological features, HIV infection was discussed in more detail. Risk groups for mentioned infections are: health workers, drug addicts, newborns of infected pregnant women, homosexuals, recipients of organs and blood transfusions as well as tattoos and body piercing fans. Unfortunately, pre-exposure prophylaxis for all these infections has not yet been developed by pharmaceutical industry. Consequently, the infections are spreading relentlessly, especially in less developed parts of the world where the awareness of such diseases is practically nonexistent. Diagnostics of the infections, which has developed to an enviable level, relies on serological and molecular laboratory diagnostics. Serological tests that are performed routinely are ELISA and IFA tests; molecular ones are PCR, TMA and Western blotting. The biggest advantage of diagnostic procedures is the development of point-of-care tests (POCT), while their biggest problem is the phenomenon of the diagnostic window (window period).