1. Laboratory of Clinical Biochemistry, Stavanger University Hospital, Stavanger, Norway;
2. Laboratory of Clinical Biochemistry, Haukeland University Hospital, Bergen, Norway;
3. The Norwegian Quality Improvement of Primary Care Laboratories (NOKLUS), Department of Public Health and Primary Health Care, University of Bergen, Bergen, Norway;
4. Department of Gynaecology, Haukeland University Hospital, Bergen, Norway;
5. Department of Medicine, Haukeland University Hospital, Bergen, Norway