The JAK2 V617F test is used to help diagnose the Myeloproliferative disorders (MPDs) polycythemia vera (PV), essential thrombocythemia (ET), and agnogenic myeloid metaplasis (primary myelofibrosis, PMF).It may be ordered as a follow up test if a person has an increased hemoglobin and/or platelet count and the doctor suspects that the person may have an MPD. This test may be used along with other tests such as bone marrow aspiration and biopsy, Erythropoietin, Complete blood count and Myeleproliferative leukemia mutation when a doctor suspects that a person has PV,ET or PMF because routine laboratory results such as a CBC reveal abnormal results associated with these MPDs and/or because the person has signs and symptoms that suggests an MPD.