[1] Charles Univ Prague, Inst Clin Biochem & Lab Diagnost, Prague, Czech Republic
[2] Charles Univ Prague, Inst Med Biochem, Prague, Czech Republic
[3] Stanford Univ, Dept Pediat, Sch Med, Stanford, CA 94305 USA
[4] Charles Univ Prague, Dept Internal Med 4, Prague, Czech Republic
[5] Gen Fac Hosp, Prague, Czech Republic