The differential diagnosis of infectious and noninfectious ethiology of an injlammation is difficult problem in many clinical situations. In the nineties new important marker - procalcitonin - appears. Although its physiological role and regulation of its production is not sufficiently explained, procalcitonin has been shown to be important, sensitive and specific marker of the bacterial infection triggering a systemicinjlammatory reaction in the body. Nowadays procalcitonin is believed to be more specific marker of the severity of sepsis than interleukin-h or C-reactive protein. The determination of procalcitonin concentration is of important value for the diagnostic algorithm in critically ill patienxs and for antibiotic therapy.

        Key words: procalcitonin - sepsis - systemic injlammatory response syndrom - differential diagnosis