The immature platelet fraction is a useful marker for predicting the timing of platelet recovery in patients with cancer after chemotherapy and hematopoietic stem cell transplantation.

Prediction of the timing of platelet recovery after chemotherapy and hematopoietic stem cell transplantation (HSCT) allows for optimal platelet transfusion. We assessed the clinical utility of the percentage value of the immature platelet fraction (IPF%) monitored using an XE-2100 automated hematology analyzer to predict the timing of platelet recovery after chemotherapy and HSCT. The IPF% was serially monitored in 31 patients with cancer who received 66 courses of chemotherapy and HSCT. In patients with cancer undergoing chemotherapy and HSCT, a transient increase in IPF% was observed 1-11 days prior to platelet recovery (>30 × 10⁹ /l). In patients undergoing chemotherapy with a peak IPF% >10%, platelet recovery occurred significantly earlier than in those with IPF% peak values ≤10% (median periods were 2 and 5 days; P < 0.05). Platelet recovery appears to occur earlier in patients undergoing HSCT with a peak IPF% >10% than in those with IPF% peak values ≤10% (median periods were 2 and 6 days). Thus, the IPF% peak value is a useful parameter for predicting the timing of platelet recovery after chemotherapy and HSCT and has the potential to facilitate optimal platelet transfusion.