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Updated: Aug 17, 2026
Routine Screening Method for Microparticles in Platelet Transfusions
Published on: January 31, 2018
Development of a time-resolved immunofluorometric assay for quantifying platelet-derived microparticles in human
Annika E Michelsen1, Ragnhild Wergeland, Oddvar Stokke
1Research Institute for Internal Medicine, University of Oslo, Rikshospitalet, N-0027 Oslo, Norway. a.e.michelsen@biokjemi.uio.no
Abstract:
Platelet-derived microparticles (PMPs) are considered a marker of platelet activation. They vary considerably in size, and flow cytometry, the predominant method used to assay PMPs, is only detecting larger PMPs (>0.1 microm). We describe here a method that quantifies the amount of PMP-located GPIIb antigen in detergent-treated platelet-free plasma (PPP) by means of a one-step time-resolved immunofluorometric assay (TR-IFMA). This assay uses a streptavidin-coated microwell plate and two different monoclonal antibodies to GPIIb (CD41), one conjugated to biotin and the other labeled with europium ion. A wide linear range standard curve with low background and a high sensitivity was obtained. Pre-assay ultracentrifugation or filtration of PPP extensively reduced the fluorometric signal, indicating that the GPIIb antigen is mainly particle-located. A strong correlation between the amount of GPIIb and PMP as detected by flow cytometry was found. Consequently, the assay can be used to study PMP-related phenomena and, in contrast to flow cytometry, can be used on frozen samples and is independent of PMP size.
