Test Details: This test is indicated in suspected cases of bone marrow disorder, especially essential thrombocythemia (ET) or primary myelofibrosis (PMF). PV, ET, and PMF are stem cell–derived clonal disorders and have been associated with various gene mutations, including JAK2, MPL, CALR etc. All the mutations identified so far occur in exon 9 of CALR gene. This test helps in the prognostication of PMF and thrombosis risk assessment in ET.