1. Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz , Graz , Austria
2. and Institute of Clinical Chemistry and Laboratory Medicine, General Hospital Hochsteiermark , Leoben , Austria
3. Department of Nephrology and Clinical Immunology , Klinikum München-Harlaching , Munich , Germany
4. Synlab Academy, Synlab Holding Deutschland GmbH , Mannheim , Germany
5. Medical Clinic V (Nephrology, Rheumatology, Endocrinology, Hypertensiology, Diabetology, Lipidology), Medical Faculty Mannheim , University of Heidelberg , Heidelberg , Germany
6. Department of Internal Medicine, Division of Nephrology , Medical University of Graz , Graz , Austria