pediatrics
Perinatal Polycythemia and Hyperviscosity Syndrome
Diagnosis
Hematocrit Clinical evaluation Diagnosis of polycythemia is by arterial or venous (not capillary) hematocrit because capillary samples often overestimate hematocrit. Most published studies of polycythemia use spun hematocrits, which are no longer routinely done and are generally higher than those done on automated counters. Diagnosis of hyperviscosity syndrome is clinical. Laboratory measure of viscosity is not readily available. Other laboratory abnormalities may include low blood glucose and calcium ion levels, red blood cell (RBC) lysis, thrombocytopenia (secondary to consumption with thrombosis), Neonatal Hyperbilirubinemia (caused by turnover of a higher number of RBCs), and reticulocytosis and increased peripheral nucleated RBCs (caused by increased erythropoiesis secondary to fetal hypoxia). 