Adult liver recipients were randomized to standard practice ( control group ; n = @ ) or serial immune function testing ( interventional group ; n = @ ) performed with a commercially available in vitro diagnostic assay ( ImmuKnow ; Viracor-IBT Laboratories , Lee 's Summit , MO ) before transplantation , immediately after surgery and at day @ , weeks @ to @ , @ , and @ , and months @ to @ , @ , and @ .