[1] Univ Minnesota, Sch Med, Hennepin Cty Med Ctr, Dept Lab Med & Pathol, Minneapolis, MN 55455 USA
[2] Univ Calif San Francisco, Dept Lab Med, San Francisco, CA 94143 USA
[3] San Francisco Gen Hosp, San Francisco, CA 94110 USA
[4] St George Hosp, London, England
[5] Mayo Clin, Dept Med, CV Div, Rochester, MN USA
[6] Mayo Clin, CCLS Div, Rochester, MN USA
[7] Brigham & Womens Hosp, Dept Med, Div Cardiovasc, Boston, MA 02115 USA