1. Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg , Gothenburg , Sweden
2. Department of Clinical Chemistry, Sahlgrenska University Hospital , Gothenburg , Sweden
3. Department of Laboratory Medicine, Institute of Biomedicine, University of Gothenburg , Gothenburg , Sweden
4. Division of Clinical Chemistry, Department of Biomedical and Clinical Sciences, Faculty of Medicine and Health Sciences, Linköping University , Linköping , Sweden
5. Department of Medical Sciences, Clinical Chemistry, Uppsala University , Uppsala , Sweden
6. External Quality Assurance in Laboratory Medicine in Sweden (EQUALIS) , Uppsala , Sweden