Medical Clinic V (Nephrology, Hypertensiology, Endocrinology, Diabetolgy, and Rheumatology), Mannheim Medical Faculty, University of Heidelberg, Germany, Synlab Academy, Synlab Services GmbH, Mannheim and Augsburg, Germany, Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Austria (At 2015-05-15)