[1] Columbia Univ Coll Phys & Surg, Dept Med, New York, NY 10032 USA
[2] Columbia Univ Coll Phys & Surg, Dept Pathol, New York, NY 10032 USA
[3] Quest Diagnost Inc, Teterboro, NJ USA
[4] Virginia Commonwealth Univ, Med Ctr, Div Gastroenterol Hepatol & Nutr, Richmond, VA USA