Immature platelet fraction: A useful marker for identifying the cause of thrombocytopenia and predicting platelet recovery

INTRODUCTION: The assessment of bone marrow thrombopoietic activity in patients with thrombocytopenia is necessary to achieve an accurate diagnosis and administer effective treatment. We evaluated the discriminatory power of the immature platelet fraction (IPF) in differentiating hyperdestructive/consumptive thrombocytopenia from hypoproductive thrombocytopenia and its potential use as a predictive marker for platelet recovery. METHODS: In this observational study, platelet indices, including IPF, were measured in 105 healthy individuals, 27 patients with hyperdestructive/consumptive thrombocytopenia (all with immune thrombocytopenic purpura [ITP]), and 35 patients with hypoproductive thrombocytopenia (5 with aplastic anemia and 30 with cancer who were undergoing chemotherapy) using a Sysmex XN-3000 hematology analyzer. RESULTS: The platelet distribution width, mean platelet volume, platelet large cell ratio, IPF, and absolute immature platelet count (AIPC) were significantly higher in the hyperdestructive/consumptive thrombocytopenia group than in the hypoproductive thrombocytopenia group (P < .001). The IPF showed the highest difference between the two patient groups (200%). Receiver operating characteristics analysis that showed the IPF had the largest area under the curve among all the platelet indices analyzed; its cut-off value was 2.3%. The IPF decreased 3 to 4 days in advance of platelet count elevation in patients with ITP, whereas the delta AIPC increased 3 days in advance. Furthermore, the IPF and delta AIPC increased 5.5 days and 8.5 days, respectively, before platelet counts increased up to 130.0 × 10(9)/L in cancer patients receiving chemotherapy. CONCLUSION: These data demonstrated that the IPF and delta AIPC are both excellent indicators of the etiology of thrombocytopenia and predictive markers for platelet recovery.