Flow rate calibration to determine cell-derived microparticles and homogeneity of blood components.

BACKGROUND: Cell-derived microparticles (MPs) are currently of great interest to screening transfusion donors and blood components. However, the current approach to counting MPs is not affordable for routine laboratory use due to its high cost. AIM: The current study aimed to investigate the potential use of flow-rate calibration for counting MPs in whole blood, packed red blood cells (PRBCs), and platelet concentrates (PCs). METHODS: The accuracy of flow-rate calibration was investigated by comparing the platelet counts of an automated counter and a flow-rate calibrator. The concentration of MPs and their origins in whole blood (n=100), PRBCs (n=100), and PCs (n=92) were determined using a FACSCalibur. The MPs' fold-changes were calculated to assess the homogeneity of the blood components. RESULTS: Comparing the platelet counts conducted by automated counting and flow-rate calibration showed an r2 of 0.6 (y=0.69x+97,620). The CVs of the within-run and between-run variations of flow-rate calibration were 8.2% and 12.1%, respectively. The Bland-Altman plot showed a mean bias of -31,142platelets/µl. MP enumeration revealed both the difference in MP levels and their origins in whole blood, PRBCs, and PCs. Screening the blood components demonstrated high heterogeneity of the MP levels in PCs when compared to whole blood and PRBCs. CONCLUSIONS: The results of the present study suggest the accuracy and precision of flow-rate calibration for enumerating MPs. This flow-rate approach is affordable for assessing the homogeneity of MPs in blood components in routine laboratory practice.