The role of erythropoietin levels and other hematological factors in the diagnosis of polycythemia vera in Iraqi patients

BACKGROUND: According to the World Health Organization (WHO), erythropoietin (EPO) is only a minor criterion for the diagnosis of polycythemia vera (PV), but its diagnostic validity is controversial. OBJECTIVES: The objective was to assess the diagnostic accuracy of EPO levels and the different combinations of the laboratory and clinical criteria, defined by the latest WHO report, as markers for the diagnosis of PV in Iraqi patients. PATIENTS, MATERIALS AND METHODS: This cross-sectional study included 158 myeloproliferative neoplasm-suspected patients (48 PV, 47 essential thrombocythemia, 25 secondary thrombocytosis, and 35 nonclonal erythrocytosis). Patients were assessed for the presence of Janus Kinase 2 (JAK2) V617F mutation. Subsequently, JAK2V617F-negative patients were evaluated for the presence of JAK2 exon 12 mutations. Plasma EPO was measured in PV and nonclonal erythrocytosis patients. RESULTS: Male was more prevalent among the nonclonal erythrocytosis patients. PV patients were older and had higher levels of all hematological variables examined in the study. Although all obtained EPO levels were normal, PV patients had significantly lower levels of EPO than nonclonal erythrocytosis. In addition, the hemoglobin and hematocrit had a better diagnostic accuracy than EPO levels in both male and female patients with PV. Furthermore, a better diagnostic accuracy was obtained when JAK2 mutation status was added to the evaluation of hemoglobin or hematocrit. CONCLUSION: The low EPO level is not a good predictive marker for PV. Hemoglobin and hematocrit had equal predictive validity in the diagnosis of PV. It is convenient to evaluate JAK2 mutation as one of the major criteria in the diagnosis of PV.