Cardiac troponin T (cTnT) is a cardio-specific myofibrillar protein known to be elevated early after heart transplantation and during cardiac allograft rejection. cTnT determination in heart allograft recipients showed elevated levels in patients with higher degrees of graft rejection (International Society for Heart and Lung Transplantation grades >/=3A-4). Subgroup analyses revealed demographic patient characteristics markedly improving the diagnostic efficiency of cTnT measurement for rejection monitoring, including male recipient gender, recipient age <60 yr, female donor gender and donor age >/= 33 yr. The clinical utility of these parameters was confirmed by longitudinal patient data and may help to select recipients most likely to benefit from cTnT rejection surveillance.