Syphilis is a general chronic disease caused by bacteria from the family Spirochaetaceae, genus Treponema. Pathogenic representatives of the genus include, due to the marked agreement of DNA sequences (more than 90%) a crossed reactivity of serological tests. The increase in incidence of syphilis in the Czech Republic during the last decade of the 20th century puts increased demands on precision, early character and reliability of diagnosis. In addition to direct examination methods for uptake of the pathogenic organism in particular in direct diagnosis of the antibody response in serum as well as cerebrospinal fluid are decisive. On their selection depends the success when assessing the disease in the population and in particular the most carefully investigated groups - blood and organ donors, pregnant women, neonates. One of the ways how to evaluate the quality of field laboratories is External Quality Control System in Activities of Laboratories Engaged in Medical Microbiology and Parasitology

        Key words: Treponema pallidum subsp. pallidum, incidence of syphilis, direct and indirect diagnosis, EQC system.