1. Department of Analytical Chemistry, University of Chemistry and Technology Prague, Technická 5, 16628 Prague, Czech Republic
2. Department of Oncology, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, U Nemocnice 2, 12800 Prague, Czech Republic
3. Fourth Internal Clinic—Gastroenterology and Hepatology, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, U Nemocnice 2, 12800 Prague, Czech Republic