[1] Univ Minnesota, Sch Med, Hennepin Cty Med Ctr, Clin Labs, Minneapolis, MN 55415 USA
[2] Univ Maryland, Sch Med, Baltimore, MD 21201 USA
[3] Mayo Clin & Mayo Coll Med, Rochester, MN USA
[4] Innsbruck Med Univ, Clin Div Cardiol, Dept Internal Med, Innsbruck, Austria
[5] Univ Autonoma Barcelona, Hosp Santa Creu & St Pau, Dept Biochem, E-08193 Barcelona, Spain
[6] Azienda Osped Spedali Civili, Dipartimento Med & Lab, Lab Anal Chim Clin, Brescia, Italy
[7] Royal Brisbane & Womens Hosp, Chem Pathol Dept Pathol, Brisbane, Qld, Australia
[8] Univ Calif San Francisco, San Francisco Gen Hosp, San Francisco, CA USA