[1] Odense Univ Hosp, Dept Clin Biochem, DK-5000 Odense, Denmark
[2] Univ Bergen, NOKLUS, Norwegian Ctr External Qual Assurance Primary Car, Div Gen Practice, N-5020 Bergen, Norway
[3] Ctr Med Prevent, Lab Biol Clin, F-54501 Vandoeuvre Les Nancy, France