Circulating tissue factor, tissue factor pathway inhibitor and D-dimer in umbilical cord blood of normal term neonates and adult plasma.

The investigation of many hemostatic defects in newborns is restricted by the lack of normal reference values. The coagulation system of the neonate differs in many ways from that of the adult. The present study was designed to compare the concentrations of tissue factor (TF), tissue factor pathway inhibitor (TFPI) and D-dimer (DD) in the umbilical cord blood of healthy newborns and in adult plasma. TF antigen was quantified using an in-house enzyme-linked immunosorbent assay, whereas TFPI and DD levels were measured with commercial kits. The mean TF level in cord blood (mean standard deviation, 183.94 103.63 pg/ml) was significantly higher ( = 0.008) than that in adults (136.64 65.09 pg/ml). Cord blood exhibited enhanced fibrinolysis, as was reflected by a significantly higher level of DD (924.57 733.87 ng/ml, 0.001) than that in adults (45.57 17.21 ng/ml). Conversely, cord blood (30.88 10.16 ng/ml) demonstrated significantly lower ( 0.001) TFPI levels than that in adults (55.77 21.16 ng/ml). However, no significant differences of these three hemostatic markers were noted between both gender groups in newborns and adults. Our findings indicate that an active and dynamic state of hemostasis exists in cord blood, as the fluidity of cord blood remains preserved in the presence of birth injury.