Interpretation of clotting tests in the neonate.

There are significant differences between the coagulation system in neonates compared with children and adults. Abnormalities of standard coagulation tests are common within the neonatal population. The laboratory tests of activated partial thromboplastin time (aPTT) and prothrombin time (PT) were developed to investigate coagulation factor deficiencies in patients with a known bleeding history, and their significance and applied clinical value in predicting bleeding (or thrombotic) risk in critically ill patients is weak. Routine screening of coagulation on admission to the neonatal intensive care unit leads to increased use of plasma for transfusion. Fresh frozen plasma (FFP) is a human donor plasma frozen within a short specified time period after collection (often 8 h) and then stored at -30°C. FFP has little effect on correcting abnormal coagulation tests when mild and moderate abnormalities of PT are documented in neonates. There is little evidence of effectiveness of FFP in neonates. A large trial by the Northern Neonatal Nursing Initiative assessed the use of prophylactic FFP in preterm infants and reported no improvement in clinical outcomes in terms of mortality or severe disability. An appropriate FFP transfusion strategy in neonates should be one that emphasises the therapeutic use in the face of bleeding rather than prophylactic use in association with abnormalities of standard coagulation tests that have very limited predictive value for bleeding.