[1] Case Western Reserve Univ, Univ Hosp Case Med Ctr, Div Gastroenterol & Liver Dis, Cleveland, OH 44106 USA
[2] Univ Pittsburgh, Shadyside Hosp, Med Ctr, Div Internal Med, Pittsburgh, PA USA
[3] Massachusetts Gen Hosp, Div Gastroenterol & Hepatol, Boston, MA 02114 USA
[4] John H Stroger Jr Hosp Cook Cty, Div Internal Med, Chicago, IL USA
[5] Mayo Clin, Dept Lab Med & Pathol, Rochester, MN USA
[6] Mayo Clin, Div Gastroenterol & Hepatol, Rochester, MN USA