Incidence of bacterial infections in hospitalised patients with liver disease is high. Due to a liver dysfunction immune reactivity is significantly impaired and bacterial infections are more frequent. Also incidence of nosocomial infections is higher in patients with liver disease compared to patients hospitalised for other conditions. To make a differential diagnosis of infectious and noninfectious aetiology of an inflammation is very difficult. Characteristic laboratory tests for bacterial infection include test of a number of leucocytes in peripheral blood, differential count of leucocytes, erythrocyte sedimentation, procalcitonin, C-reactive protein, tumor necrosis factor alpha, interleukin-1, interleukin-6, interleukin-8, and complement fragment C3a. Clinically the most significant are C-reactive protein test and procalcitonin test. Procalcitonin is a protein, a calcitonin precursor, which is in healthy individuals produced by cells of thyroid gland. A halflife of procalcitonin in serum is 20 – 24 hours which makes it suitable for daily monitoring and enables to control a course of treatment and to distinguish bacterial infection from other types of inflammations. Procalcitonin levels rise in bacterial, parasite, and yeast infections. Elevated procalcitonin levels appear only in inflammations of an infectious etiology with systemic signs. In patients with liver cirrhosis bacterial infections are more frequent. They usually include spontaneous bacterial peritonitis, infection of the respiratory system, urinary infections, and bacteremia. A timely proof of a bacterial infection and an appropriate and effective antibiotic therapy lead to an improvement of the general state of a patient and to his/her better prognosis. Procalcitonin determination is appropriate for diagnosing infections and control of treatment.

        Key words: Procalcitonin - Bacterial infection - Liver cirrhosis