Immature platelets do not reliably predict platelet recovery in patients with intensive chemotherapy or stem cell transplantation

Background and Objectives It has been reported that immature platelets may indicate imminent platelet (PLT) recovery following intensive chemotherapy and/or haematopoietic stem cell transplantation with the perspective to withhold unnecessary transfusions. The objective of our prospective study was to test immature PLTs as measured by two haematology analysers to predict PLT recovery. Material and Methods This study monitored 51 courses of severe thrombocytopenia after chemotherapy in 35 adult haematology/oncology patients starting at a PLT count < 70 x 10(9)/l until PLT recovery (>20 x 10(9)/l) or discharge from hospital. Immature platelets as measured by immature platelet fraction (IPF) (Sysmex XE-5000) and retPLT (Abbott CD-Sapphire) as well as reticulocyte and leucocyte count were evaluated regarding their usefulness to predict PLT recovery. Furthermore, the influence of platelet concentrate (PC) transfusions upon IPF and retPLT was assessed. Results With beginning of thrombocytopenia, most patients demonstrated elevated IPF% (median 8.6%) and retPLT% (median 6.8%). These elevated values significantly dropped after transfusions of PCs. IPF and retPLT values during nadir and at imminent PLT recovery were largely overlapping and receiver operating characteristics analysis demonstrated poor separation between both clinical situations. A reasonable cut-off could not be established to prospectively predict imminent PLT recovery for either of the parameters investigated. Conclusion Measurements of IPF and retPLT lack predictive power regarding imminent PLT recovery in patients with severe thrombocytopenia following intensive chemotherapy. Decisions regarding prophylactic PC transfusions should not be based on these parameters.