[1] UNIV LEIDEN HOSP,DEPT GASTROENTEROL HEPATOL,NL-2300 RC LEIDEN,NETHERLANDS
[2] UNIV LEIDEN HOSP,DEPT GEN SURG,NL-2300 RC LEIDEN,NETHERLANDS
[3] UNIV LEIDEN HOSP,DEPT CLIN CHEM,NL-2300 RC LEIDEN,NETHERLANDS
[4] UNIV UTRECHT HOSP,DEPT GEN SURG,UTRECHT,NETHERLANDS
[5] UNIV UTRECHT HOSP,DEPT GASTROENTEROL HEPATOL,UTRECHT,NETHERLANDS
[6] UNIV UTRECHT HOSP,DEPT CLIN CHEM,UTRECHT,NETHERLANDS