1. Institute of Medical Technology, University of Tampere and Tampere University Hospital, Biokatu 6, 33520 Tampere, Finland
2. Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, U.S.A.
3. Department of Clinical Chemistry, University of Oulu, Kajaanintie 50, 90220 Oulu, Finland