1. Clinic of Hematology, “St. Marina” University Hospital, 9010 Varna, Bulgaria
2. Department of Clinical Laboratory, Faculty of Medicine, Medical University-Varna, 9002 Varna, Bulgaria
3. Second Department of Internal Diseases, Faculty of Medicine, Medical University-Varna, 9002 Varna, Bulgaria
4. Department of Biochemistry, Molecular Medicine and Nutrigenomics, Faculty of Pharmacy, Medical University-Varna, 9000 Varna, Bulgaria