High correlation between 2 flow cytometry platforms in the microparticles analysis using a new calibrated beads strategy

Microparticles (MPs) are potential noninvasive biomarkers for diagnosis or prognosis in pathologic conditions. However, the lack of standardization of the preanalytical and analytical methods leads to a wide variability in MPs results. The recently developed Megamix-Plus beads, a new bead-based standardization tool optimized to specific types of flow cytometers, could help circumvent this problem. The aim of the present study was to determine whether the number of total MPs and platelet-derived MPs (PMPs) is similar using 2 different cytometer platforms calibrated with the Megamix-Plus beads. Blood samples from 65 patients with deep venous thrombosis were collected and processed to obtain platelet poor plasma (PPP). The number of total MPs and PMPs in each PPP sample was measured using 2 flow cytometers. Megamix-Plus side scatter channel beads were used to calibrate the LSRFortessa flow cytometer from Becton Dickinson, whereas Megamix-Plus forward scatter channel beads were applied to the Navios flow cytometer from Beckman Coulter. High correlation of total MPs and PMPs values between the flow cytometers was found (r = 0.908, P < 0.01 and r = 0.910, P < 0.001, respectively). However, the absolute numbers of total MPs and PMPs were significantly higher measured with the Navios flow cytometer compared with the LSRFortessa cytometer. Therefore, both platforms are valid for MPs determination in general, although a similar platform with the same calibration tool could be a better choice for multicenter studies.