1. University of Health Sciences, Department of Internal Medicine, Division of Nephrology, Ankara, Turkey
2. Bulent Ecevit University Medical School, Department of Internal Medicine, Zonguldak, Turkey
3. Bulent Ecevit University Medical School, Department of Medical Biochemistry, Zonguldak, Turkey
4. Zonguldak Atatürk State Hospital, Department of Nephrology, Zonguldak, Turkey
5. Samsun Educational and Research Hospital, Department of Nephrology, Samsun, Turkey