Plasma thrombopoietin levels as additional tool in clinical management of thrombocytopenic neonates.

Plasma thrombopoietin (Tpo) levels distinguish thrombocytopenia resulting from increased platelet destruction or decreased platelet production. We investigated whether measuring plasma Tpo levels in thrombocytopenic newborns is of diagnostic value to establish the underlying mechanism of thrombocytopenia. Tpo levels were measured with in-house developed ELISA in samples referred to our center because of thrombocytopenia noticed in the first 10 days of life. Clinical data were collected. Plasma Tpo levels <128 AU/ml were found in the majority (92%) of 121 newborns with immune-mediated thrombocytopenia (n = 104) and thrombocytopenia due to bacterial infections (n = 7); increased plasma Tpo levels (≥128 AU/ml) were found in thrombocytopenic newborns with severe asphyxia (n = 24). Highly increased plasma Tpo levels (>200 AU/ml) were found in thrombocytopenic neonates with congenital viral infections (n = 22) or amegakaryocytosis (n = 6). A plasma Tpo level <128 AU/ml excludes (negative predictive value 96%, 95% CI 90-99) severe asphyxia, congenital viral infections and amegakaryocytosis as the cause for thrombocytopenia in newborns. Increased plasma Tpo levels indicate that thrombocytopenia in newborns, as a result of various nonimmune disorders, is often caused by (temporary) bone marrow suppression/failure. Measurement of plasma Tpo levels provides the clinician with an additional tool to decide on the differential diagnosis, the necessity for subsequent diagnostics and treatment in neonates with thrombocytopenia.