1. Department of Clinical Chemistry, Ghent University Hospital, Ghent, Belgium
2. Andrology Research Unit, Centre for Endocrinology and Diabetes, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
3. Department of Endocrinology, Diabetes, and Metabolism, University of Verona, Verona, Italy
4. Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy
5. Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine KU Leuven, Leuven, Belgium
6. Department of Endocrinology, Ghent University Hospital, Ghent, Belgium