1. Laboratory Dr. Limbach and Colleagues , Heidelberg , Germany
2. Medical Faculty Mannheim of Heidelberg University , Theodor Kutzer Ufer 1-3 , 68167 Mannheim , Germany
3. UGC Análisis Clínicos intercentros , Hospital Universitario Campus de la Salud , Granada , Spain
4. Roche Diagnostics GmbH , Mannheim , Germany