1. Department of Clinical Biochemistry, Nordsjællands Hospital, University of Copenhagen, Hillerød, Denmark
2. Department of Clinical Research, Nordsjællands Hospital, University of Copenhagen, Hillerød, Denmark
3. Department of Oncology, Herlev & Gentofte Hospital, University of Copenhagen, Herlev, Denmark
4. Norwegian Quality Improvement Primary Care Laboratories (NOKLUS), Section for General Practice, University of Bergen, Bergen, Norway