Thrombin generation and procoagulant phospholipids in patients with essential thrombocythemia and reactive thrombocytosis

Thrombocytosis is a commonly encountered clinical scenario and can be either a secondary process (reactive thrombocytosis), or due to clonal disorder (i.e., essential thrombocythemia). This distinction is important as it carries implications for evaluation, prognosis and treatment. In this study we compared procoagulant potential in essential thrombocythemia and reactive thrombocytosis by measuring the thrombin generation and the level of circulating procoagulant phospholipids with functional tests. Twenty nine patients with essential thrombocythemia and 24 with reactive thrombocytosis were studied. Thrombin generation was determined by calibrated automated thrombography. Procoagulant phospholipids were detected by a chronometric standardised method (STA‐Procoag‐PPL). Patients with reactive thrombocytosis had a longer lag time, higher endogenous thrombin potential, peak of thrombin generation and velocity index than patients with essential thrombocythemia. The level of circulating procoagulant phospholipids was increased in patients with essential thrombocythemia as observed with the procoagulant phospholipids assay. Each parameter was analysed using ROC curves. Highest areas under the curve (AUC) were found for lag time and procoagulant phospholipids ratio (0.817 and 0.853, respectively), associated with high negative predictive value for ET (92.3% and 80%, respectively). In conclusion, patients with essential thrombocythemia and reactive thrombocytosis displayed significant differences in terms of thrombin generation and levels of procoagulant phospholipids. Among these parameters, lag time and procoagulant phospholipids ratio could help to differentiate between reactive thrombocytosis and essential thrombocythemia patients. Am. J. Hematol. 88:1007–1011, 2013. © 2013 Wiley Periodicals, Inc.