[1] Chair Comm Educ & Training, Zagreb 10000, Croatia
[2] Univ Hosp Sestre Milosrdnice, Univ Dept Chem, Sch Med, Zagreb, Croatia
[3] Univ Milan, Ctr Metrol Traceabil Lab Med CIRME, Milan, Italy
[4] Linkoping Univ, Dept Clin Chem, Linkoping, Sweden
[5] Linkoping Univ, Dept Clin & Expt Med, Linkoping, Sweden
[6] Univ Verona, Lab Clin Biochem, Dept Neurol Biomed & Movement Sci, I-37100 Verona, Italy
[7] Sestre Milosrdnice Univ Hosp Ctr, Univ Dept Chem, Zagreb, Croatia
[8] Equalis, Uppsala, Sweden
[9] Westgard QC, Client Serv & Technol, Orange, CT USA