1. Department of Medical Biochemistry, Faculty of Pharmacy, University of Belgrade, 11000 Belgrade, Serbia
2. Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia
3. Department of Gastroenterology and Hepatology, Clinic for Internal Medicine, Clinical Hospital Center Zemun, 11080 Belgrade, Serbia
4. Department of Laboratory Diagnostics, Clinical Hospital Center Zemun, 11080 Belgrade, Serbia
5. Clinical Department for Gastroenterology and Hepatology, University Medical Center Zvezdara, 11000 Belgrade, Serbia