1. Department of Nephrology, University Clinical Centre of Serbia, 11000 Belgrade, Serbia
2. Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia
3. Special Hospital for Internal Diseases, 11550 Lazarevac, Serbia
4. Fresenius Medical Care Dialysis Center, 76230 Šamac, Bosnia and Herzegovina
5. Centre for Medical Biochemistry, University Clinical Centre of Serbia, 11000 Belgrade, Serbia
6. Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia
7. Uromedica Polyclinic Belgrade, 11000 Belgrade, Serbia