Immature Platelet Fraction (IPF) as Novel Laboratory Parameter for Managing Early Onset Thrombocytopenia in Very Low Birth Weight Infants

Thrombocytopenia (platelet count <150/nl) is one of the most common hematologic problems in preterm and term neonates and affects 18 to 35% of all patients admitted to neonatal intensive care units (NICU). Thrombocytopenia is more than twice common in extremely low birth weight infants (ELBW; <1000g) as reported among the general NICU population. Among thrombocytopenic ELBW infants almost 40% suffer from severe thrombocytopenia as defined by a platelet count <50nl. The risk for hemorrhage, which may cause acute life-threatening complications and/or life-long disability in more than 15%, is difficult to assess, because it is closely related to the gestational and postnatal age of the neonate as well as the cause of the thrombocytopenia and the severity of concurrent conditions. From routine full blood counts of premature (birth weight <1500g) and full term babies we additionally determined platelet counts, IPF, MPV, NRBC and reticulocyte counts. On the basis of individual IPF and platelet counts we were able to predict the platelet counts of the following day. In non-thrombocytopenic preterm and term neonates no significant changes in IPF values were found during the first week of life. In the first week, thrombocytopenic neonates displayed higher IPF values than neonates with normal plaletet counts. We hypothesize that IPF is higher in neonates with chronic hypoxia as leading cause for thrombocytopenia and lower in case of perinatal infections. IPF could be a novel parameter in routine diagnostics available at a 24/7 basis in VLBW infants and may be valuable in identifying the underlying pathomechanism of various thrombocytopenias and in clinical decision making on platelet transfusions.