1. Laboratory Diagnostics Center, RWTH-University Hospital Aachen, Aachen and Medical Care Center, Dr Stein and colleagues, Mönchengladbach, Germany
2. Clinic for Internal Medicine and Clinical Intensive Care Medicine, Sankt Antonius Hospital Eschweiler, Eschweiler, Germany
3. Department of Gynecological Endocrinology and Reproductive Medicine, RWTH-University Hospital Aachen, Aachen, Germany
4. Division of Nephrology and Clinical Immunology, RWTH-University Hospital Aachen, Aachen, Germany