Comparison of assays measuring extracellular vesicle-tissue factor in plasma samples: Communication from the ISTH SSC Subcommittee on Vascular Biology
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Abstract
BACKGROUND: Scientific and clinical interest in extracellular vesicles (EVs) is growing. EVs that expose tissue factor (TF) bind factor VII/VIIa and can trigger coagulation. Highly procoagulant TF-exposing EVs are detectable in the circulation in various diseases, such as sepsis, COVID-19, or cancer. Many in-house and commercially available assays have been developed to measure EV-TF activity and antigen, but only a few studies have compared some of these assays.
OBJECTIVES: The International Society on Thrombosis and Haemostasis Scientific and Standardization Committee Subcommittee on Vascular Biology initiated a multicenter study to compare the sensitivity, specificity, and reproducibility of these assays.
METHODS: Platelet-depleted plasma samples were prepared from blood of healthy donors. The plasma samples were spiked either with EVs from human milk or EVs from TF-positive and TF-negative cell lines. Plasma was also prepared from whole human blood with or without lipopolysaccharide stimulation. Twenty-one laboratories measured EV-TF activity and antigen in the prepared samples using their own assays representing 18 functional and 9 antigenic assays.
RESULTS: There was a large variability in the absolute values for the different EV-TF activity and antigen assays. Activity assays had higher specificity and sensitivity compared with antigen assays. In addition, there was a large intra-assay and interassay variability. Functional assays that used a blocking anti-TF antibody or immunocapture were the most specific and sensitive. Activity assays that used immunocapture had a lower coefficient of variation compared with assays that isolated EVs by high-speed centrifugation.
CONCLUSION: Based on this multicenter study, we recommend measuring EV-TF using a functional assay in the presence of an anti-TF antibody.
Bibliographical data
Original language | English |
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ISSN | 1538-7933 |
DOIs | |
Publication status | Published - 10.2024 |
Comment Deanary
Copyright © 2024. Published by Elsevier Inc.
PubMed | 38925490 |
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