Introduction: Immature platelets in the circulation contain high levels of cytoplasmic RNA which can be stained and quantified using the Sysmex XN-series Fluorescent PLT channel (PLT-F). Based on a fluorescence flow cytometry method, it is particularly accurate for low platelet counts and is not susceptible to interference from non-platelet particles. The immature platelet fraction (IPF) is given as a percentage of the total platelet count and may give clinicians an indication of thrombopoiesis in the bone marrow.
Objective: The aim of this study was to establish %IPF reference ranges for normal adults on the Sysmex XN-series PLT-F channel.
Method: The PLT-F channel utilises an oxazine dye which penetrates platelet cell membranes and stains RNA-rich immature platelets. The fluorescent platelet count, and subsequently %IPF, is derived from this channel through a 2D plot of forward scatter (cell size) versus sideward fluorescence scatter (RNA content). In this study, whole blood samples from a total of 170 normal patients (84 males and 86 non-pregnant females) were collected in K2-EDTA and analysed on the Sysmex XN-2000. Normal patients must have had no previous abnormal results or clinical history that might affect platelet count.
Results: From this study, no significant difference (p<0.05) was found between males and females for %IPF, and the reference range for both sexes was determined to be 0.1-7.8%.
Conclusion: Measurement of the %IPF can provide an indication of thrombopoiesis in the bone marrow. Establishing normal reference ranges for the %IPF parameter on the XN-series may aid clinicians in the differential diagnosis of various platelet disorders and the status of thrombopoiesis in patients who have undergone chemotherapy or transplantation.