The discovery of the JAK2 V617F mutation has undoubtedly revolutionised the diagnosis of the classical Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) with the mutation present in greater than 95% of polycythaemia vera (PV) patients, approximately 50% of patients with essential thrombocythaemia (ET) and primary myelofibrosis (PMF) and, to a lesser degree, in a number of other myeloid malignancies such as refractory anaemia with ringed sideroblasts with thrombocytosis, chronic myelomonocytic leukaemia and acute myeloid leukaemia. Detection of this mutation is  beneficial in differentiating between a reactive haematological response and a true clonal disorder and can also serve as a target for therapeutic intervention.1 Current guidelines for the diagnosis of PV, ET and PMF maintain the requirement for inclusion and/or exclusion of numerous other clinical and laboratory parameters such as histopathological examination of a bone marrow biopsy.2–4 Molecular testing for the presence of the JAK2 V617F mutation is now not only used for …