ObjectivesWe aimed to investigate the prevalence of JAK2-V617F mutation and its association with hematologic parameters in polycythemia vera(PV), essential thrombocytosis(ET) and primary myelofibrosis(PMF) patients who have been tested for the mutation.MethodsWe retrospectively reviewed the records of 168 patients (82 males and 86 females) who were tested for JAK2-V617F mutation upon request of Hematology Clinic. JAK2-V617F mutation status, white blood cell (WBC) counts, platelet (PLT) counts, hemoglobin (Hb), hematocrit (Hct) levels and demographics of the patients were recorded.ResultsJAK2-V617F mutation was detected in 55.9% of the 168 patients. The mutation was observed in 58.2% of PV cases, in 54.4% of ET and in 54.5% of PMF cases. All patients were divided into two groups: mutation positive and negative. Age, WBC and PLT levels were significantly higher in mutation positive group (p<0.05). Age, WBC, Hb, Hct and PLT counts in PV cases with JAK2-V617F mutation, age and WBC counts in PMF cases with JAK2-V617F mutation were found to be significantly higher compared to mutation negative patients (p<0.05).ConclusionJAK2-V617F mutation is a very important parameter in diagnostic and prognostic evaluation. Thus, every patient suspected of having a myeloproliferative neoplasm should be screened for JAK2-V617F mutation.