1. Departments of Clinical Chemistry, New Cross Hospital, Wolverhampton, West Midlands, UK
2. BD Life Sciences – Preanalytical Systems, Oxford, UK
3. Department of Clinical Chemistry, Academic Medical Center, Amsterdam, the Netherlands
4. The Department of Medical Biosciences, Clinical Chemistry, Umea University, Umea, Sweden
5. Department of Clinical Pathology, São João Hospital Center, Department of Biochemistry, Faculty of Medicine, and EPI Unit, Institute of Public Health, University of Porto, Porto, Portugal
6. Laboratori Clínic Hospital Arnau de Vilanova, Lleida, Spain
7. Clinical Laboratory Diagnostic Department with Course of Molecular Medicine, First Saint Petersburg Pavlov State Medical University, St-Petersburg, Russia
8. The Norwegian EQA Program (NKK), Bergen, Norway
9. Section of Clinical Chemistry, University of Verona, Verona, Italy
10. Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark
11. Central Laboratory, Hospital Sumperk, Sumperk, Czech Republic
12. Center for Medical Biochemistry, Clinical Center of Serbia, Belgrade, Serbia
13. Department of Medical Laboratory Diagnostics, Clinical Hospital Sveti Duh, Zagreb, Croatia