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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. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: An association between pulmonary embolism (PE) and a subsequent diagnosis of cancer has been repeatedly reported. Although screening and early detection might play a pivotal part in reducing mortality from cancer, there are currently no definite data to suggest that cancer screening may improve survival rates in patients with PE. We hereby present the results of a screening program and a two-year follow-up survey for detecting occult cancer in this patient population. Materials and methods: A total of 107 patients with PE were consecutively enrolled. All subjects underwent an initial screening program followed by a two-year follow-up survey. We calculated the sensitivity of our screening program, and identified risk factors associated with occult cancer by means of logistic regression. Results: The initial screening program yielded positive results in five patients (4.7%), and four additional cases were identified during the 2-year follow-up. The overall sensitivity of our screening program in idiopathic PE was 55.5%. In the entire study cohort, the number necessary for screening was 12.1 (6.1 in idiopathic PE, and 58 in secondary PE). Logistic regression analysis revealed that a shock index ≥1 (odds ratio: 5.467; p=0.007) and idiopathic PE (odds ratio: 12.82; p=0.03) were independent risk factors for occult cancer in our PE patients. Conclusions: A simple and noninvasive screening program yields an acceptable sensitivity for detecting occult cancer in idiopathic PE patients. These results highlight the importance of screening for occult cancer in patients diagnosed with PE, especially in idiopathic forms. [Copyright &y& Elsevier]